Microcapsule suspending agent containing abamectin and fluopyram as well as preparation method and application of microcapsule suspending agent

Abstract

The invention discloses a microcapsule containing abamectin and fluopyram, a suspending agent and a preparation method and application of the microcapsule and the suspending agent, and belongs to the technical field of pesticide preparations. The invention provides a microcapsule containing abamectin and fluopyram. The microcapsule contains an active compound and a stabilizer, the active compound is prepared from abamectin and fluopyram; the stabilizing agent is prepared from dimethyl phthalate, acetyl tri-n-butyl citrate and dioctyl phthalate; the median particle size D50 of the microcapsule is 0.6 to 5.0 [mu] m, and the maximum particle size D90 of the microcapsule is 1.0 to 15.0 [mu] m; based on the micro-capsule, the invention also provides a micro-capsule suspending agent containing the micro-capsule containing abamectin and fluopyram and a preparation method of the micro-capsule suspending agent. The microcapsule suspending agent has the persistence of the active ingredients and the mobility of the microcapsules in soil during application, has a certain release amount near the depth of plant roots in the soil, and is expected to become a more effective compound pesticide preparation for preventing and treating plant root diseases.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticide formulations, and more specifically, relates to a microcapsule, suspension agent containing abamectin and fluopyram, and a preparation method and application thereof. Background Art

[0002] Abamectin is a kind of sixteen-membered macrolide compound with insecticidal, acaricidal and nematicidal activities, which was first developed by Satoshi Ōmura of Kitasato University in Japan and Merck & Co., Inc. in the United States, and is produced by fermentation of Streptomyces avermitilis. Abamectin kills insects by stimulating the release of γ-aminobutyric acid. Experiments have shown that abamectin has high activity against plant nematodes such as root-knot nematodes, root rot nematodes, cyst nematodes, stem nematodes and pine wood nematodes, and has good control effects. Abamectin has the characteristics of broad spectrum, high efficiency, low toxicity, low residue and environmental friendliness. At present, abamectin mainly exists in traditional dosage forms such as emulsifiable concentrates and microemulsions. However, after these dosage forms of abamectin are applied, they will not move to the roots of plants. It is adsorbed by the soil and decomposed by microorganisms, and the effective period is short. Therefore, there is no cumulative effect in the environment. So the use effect of the existing abamectin agents in the field is not ideal. There are reports in the prior art that abamectin is encapsulated in microcapsules, which to a certain extent improves the effective period of abamectin. However, since the plant lesions of nematodes are located at the roots of plants, the prior art has not paid attention to whether abamectin can actually reach the root lesions of plants in the soil to maximize the efficacy and control nematodes.

[0003] Fluopyram is a nematicide with a brand-new mechanism of action, belonging to the class of succinate dehydrogenase inhibitors (SDHI), and has strong nematicidal activity. Its mechanism of action: inhibits the activity of the target succinate dehydrogenase, thereby interfering with its respiratory function.

[0004] The rational compounding or mixing of insecticidal active ingredients has positive characteristics such as expanding the insecticidal spectrum, improving the control effect, extending the suitable period for pesticide application, reducing the dosage of pesticides, reducing phytotoxicity, reducing residues, and delaying the occurrence and development of pest drug resistance and resistance. Therefore, the compounding or mixing of insecticides is one of the methods to improve the above effects. The patent document with the Chinese patent application publication number CN104585190A discloses a composition for killing nematodes by compounding abamectin and fluopyram. Under specific ratios of abamectin and fluopyram, it has good toxicity effects under indoor conditions, and the field efficacy control effect on cucumber root-knot nematodes is better than that of abamectin or fluopyram alone. Although the prior art obtains a specific ratio of abamectin or fluopyram with a synergistic effect through the optimization of the ratio of the two, however, its active ingredients are still directly exposed to the soil body and adsorbed by the soil body after application, making it difficult to truly improve the effective period of the active ingredients and difficult to reach the root lesions of plants.

[0005] The patent document with the Chinese patent application publication number CN110150275A discloses a microcapsule suspension - suspension agent containing abamectin and fluxapyroxad. This microcapsule suspension - suspension agent actually prepares abamectin microcapsule suspension by encapsulating abamectin in microcapsules, and then mixes it with the fluxapyroxad suspension that is not encapsulated in microcapsules to obtain the abamectin · fluxapyroxad microcapsule suspension - suspension agent. That is to say, in this prior art, abamectin is encapsulated in microcapsules, while fluxapyroxad remains outside the microcapsules. After applying this abamectin · fluxapyroxad microcapsule suspension - suspension agent, since abamectin is encapsulated by the microcapsules, it will not be directly adsorbed by the upper soil layer. The microcapsules have a certain mobility in the soil, and during the movement, the microcapsules gradually break the wall to release abamectin, avoiding the inactivation of abamectin due to direct exposure to the external environment such as sunlight and soil pH in actual use, and effectively prolonging the effective period of abamectin. However, this prior art only solves the problem of the persistence of abamectin. After application, fluxapyroxad is still distributed in the upper layer of the soil. Affected by the external environment and the decomposition of microorganisms, it is difficult to reach the root lesion site, which affects its efficacy. In this prior art, fluxapyroxad is not encapsulated in microcapsules either, because the solubility of the fluxapyroxad technical material is relatively poor. Although the patent document with the Chinese patent application publication number CN114557342A also prepares fluxapyroxad microcapsules, the solvent used to dissolve fluxapyroxad is xylene, which is toxic and not environmentally friendly. This solution is somewhat contrary to the requirements of green environmental protection. Therefore, the prior art has not achieved dissolving the fluxapyroxad technical material with a non - toxic and green solvent and obtaining spherical microcapsules. At the same time, although these two prior arts respectively encapsulate abamectin and fluxapyroxad in microcapsules to solve the persistence problem of a single active ingredient, they also do not pay attention to the problem of whether the active ingredients can actually reach the root lesions of plants in the soil to maximize the efficacy and control nematodes. Summary of the Invention

[0006] 1. Problems to be Solved

[0007] One of the purposes of the present invention is to provide a microcapsule containing abamectin and fluxapyroxad, simultaneously dissolving and encapsulating abamectin and fluxapyroxad in the microcapsules, so that the release rates of the two technical materials in the microcapsules are basically the same, and during the release process, both are released efficiently and uniformly according to the preset proportion of the technical materials. Moreover, the particle size and the toughness of the capsule wall of the microcapsule make the microcapsule have good mobility after being applied to the soil surface, which can ensure that some active ingredients reach the root lesions of plants at a specific depth in the soil and then slowly release the technical materials, with high utilization rate and long effective period of the technical materials.

[0008] For the above purposes, the present invention further provides microcapsules containing abamectin and fluxapyroxad in powder form (such as freeze-dried powder form). Microcapsules of this form are different from the microcapsule suspension with a fixed solid content in the prior art. They can be prepared immediately before use and the solid content of the microcapsules can be adjusted according to actual needs. In production and sales, due to the better stability of the powder (such as freeze-dried powder), the microcapsule powder is more conducive to storage, transportation, various forms of circulation, and the protection of thermosensitive components.

[0009] The second object of the present invention is to provide a microcapsule suspension containing abamectin and fluxapyroxad. In this abamectin and fluxapyroxad microcapsule suspension, there are microcapsules containing abamectin and fluxapyroxad simultaneously with a specific percentage content, and the microcapsules are evenly dispersed, do not agglomerate, are not easily broken, have good storage stability, have good mobility of the original drug wrapped by the microcapsules in the soil application environment, high utilization rate of the original drug, and long effective period.

[0010] 2. Technical solutions

[0011] To solve the above problems, the technical solutions adopted by the present invention are as follows:

[0012] In the present invention, it is found that the persistence and mobility in soil of abamectin and fluxapyroxad encapsulated in the microcapsules mainly depend on the dissolution state of the technical materials in the microcapsules, the toughness of the microcapsule wall, and the microcapsule size. If the solubility of the technical materials in the microcapsules is poor, in addition to the low encapsulation rate during the preparation of the microcapsules resulting in the loss of active ingredients, when the microcapsules are applied to the soil, the capsule wall is under the dual pressure of the external soil and the internal solid, and there are also problems such as the easy breakage of the capsule wall during the release process and the technical materials existing in the solid form in the soil after release and being difficult to exert their efficacy. When the microcapsules are applied to the soil, if the toughness of the capsule wall is poor or the capsule wall is in an environment containing crystalline substances, the encapsulated technical materials are very easy to release and prone to burst release of the technical materials, resulting in most of the technical materials floating on the soil surface and being difficult to move to the lesion location of the plant roots. When the microcapsule size is too large, there will also be problems of burst release and the technical materials floating on the soil surface and being difficult to move to the lesion location of the plant roots. If the microcapsule size is too small, there will be problems that the microcapsules are not easy to break or move too deep and the technical materials are difficult to release near the root lesions. Therefore, balancing the stabilizer for dissolving the technical materials, the toughness of the microcapsule wall, and the size is the key to achieving the persistence of the technical materials and their mobility in the soil. At the same time, the dissolution state of the technical materials in the microcapsules and the toughness of the microcapsule wall are affected by the dissolution characteristics of the solvent for the technical materials and the capsule wall. We hope that the solvent has good solubility for the technical materials and can also maintain support for the toughness of the microcapsules. Coupled with the control of the microcapsule particle size, the persistence and mobility of the microcapsules can be ensured. On this basis, through research, the present invention has discovered a stabilizer group (solvent group) that can simultaneously allow the persistence and mobility of the technical materials for dissolving the technical materials in the microcapsules and stabilizing the capsule wall. Under the stabilization of this stabilizer group, microcapsules of a specific size containing both abamectin and fluxapyroxad are formed to achieve both the persistence of the active ingredients and the mobility of the microcapsules in the soil to achieve the purpose of preventing and treating plant root diseases.

[0013] [Microcapsules containing abamectin and fluxapyroxad]

[0014] Based on this, in the first aspect of the present invention, there is provided a microcapsule containing abamectin and fluxapyroxad, wherein the microcapsule contains a technical material and a stabilizer;

[0015] The technical material contains a first active ingredient and a second active ingredient; the first active ingredient contains abamectin, and the second active ingredient contains fluxapyroxad;

[0016] The stabilizer contains dimethyl phthalate, tributyl acetylcitrate, and dioctyl phthalate;

[0017] The median particle size D50 of the microcapsule is 0.6 - 5.0 μm; preferably 0.8 - 4.0 μm; more preferably 1.0 - 3.0 μm; most preferably 1.0 - 2.0 μm;

[0018] The maximum particle size D90 of the microcapsule is 1.0 to 15.0 μm, preferably 1.2 to 12.0 μm, more preferably 2.0 to 6.0 μm, and most preferably 2.5 to 5.0 μm.

[0019] For example, it is preferred that the median particle size D50 of the microcapsule is 0.6-5.0 μm, and the maximum particle size D90 is 1.0-15.0 μm; or it is preferred that the median particle size D50 of the microcapsule is 0.8-4.0 μm, and the maximum particle size D90 is 1.2-12.0 μm; or it is preferred that the median particle size D50 of the microcapsule is 1.0-3.0 μm, and the maximum particle size D90 is 2.0-6.0 μm; or it is preferred that the median particle size D50 of the microcapsule is 1.0-2.0 μm, and the maximum particle size D90 is 2.5-5.0 μm.

[0020] The technical drug referred to in the present invention may also be referred to as an active ingredient. Specifically, it refers to two substances, avermectin and fluopyram. If the amount of the technical drug or active ingredient is involved, it refers to the total amount of the two substances, avermectin and fluopyram.

[0021] Natural avermectin contains 8 components, namely avermectin A 1a , A 2a , B 1a , B 2a , A 1b , A 2b , B 1b and B 2b ; The avermectins referred to in the present invention include avermectin A 1a , A 2a , B 1a , B 2a , A 1b , A 2b , B 1b or B 2b Any one of the above, or any combination of any two or more in any proportion, such as avermectin B 1a +B 1b , where B 1a Not less than 90%, B 1b Not more than 5%, also contains other isomers of avermectin that may be present.

[0022] Fluopyram, also known as fluopyram, has a CAS number of 658066-35-4 and the structural formula is as follows:

[0023]

[0024] In the present invention, the stabilizer can also be referred to as a solvent. Specifically, it refers to dimethyl phthalate, tributyl acetylcitrate, and dioctyl phthalate.

[0025] Dimethyl phthalate has a CAS number of 131-11-3 and its structural formula is as follows:

[0026]

[0027] Tributyl acetylcitrate has a CAS number of 195511-54-7 and its structural formula is as follows:

[0028]

[0029] Dioctyl phthalate has a CAS number of 117-81-7 and its structural formula is as follows:

[0030]

[0031] It should be noted that although the compound structures in the present invention do not specifically describe chirality, those skilled in the art should recognize that there may be stereochemical configurations in these chemical structures. The names of all compounds involved in the present invention refer to all reasonable and all possible stereochemical configurations and their combinations of the compound.

[0032] In addition, it should be noted that the stabilizer in the present invention can dissolve the original drug and stabilize the microcapsule wall at the same time, so it can also be called a solvent. Among the stabilizers, dimethyl phthalate, tributyl acetylcitrate, and dioctyl phthalate all have a certain dissolving effect on abamectin and fluxapyroxad; among them, dioctyl phthalate also supports and stabilizes the toughness of the microcapsule wall of the microcapsule containing urea groups, making the microcapsule wall have a certain toughness, maintaining the thermal storage stability and cold storage stability of the microcapsule, and making the wall have a certain strength, so as to achieve the purpose of slow release of the original drug. At the same time, combined with the particle size characteristics of the microcapsule, the purpose of releasing the microcapsule at a specific depth under the soil body can be achieved. During the preparation of the microcapsule, the proportions and dosages of dimethyl phthalate, tributyl acetylcitrate, and dioctyl phthalate can be adjusted according to the percentage content of the original drugs abamectin and fluxapyroxad. For example, when the proportion of abamectin in the original drug is relatively high, the proportion of dioctyl phthalate in the solvent (stabilizer) can be appropriately increased; when the proportion of fluxapyroxad in the original drug is relatively high, the proportions of tributyl acetylcitrate and dioctyl phthalate in the solvent (stabilizer) can be appropriately increased. In addition, considering from the perspective of the toughness of the microcapsule wall, in the mixed solvent of dimethyl phthalate, tributyl acetylcitrate, and dioctyl phthalate, the weight percentage of dioctyl phthalate in the mixed solvent should not be less than 10%, but considering from the cost perspective, the weight percentage of dioctyl phthalate in the mixed solvent is preferably not more than 35%. At the same time, as a general principle, when preparing the microcapsule, the amount of the solvent (stabilizer) used to dissolve the original drug should generally not be higher than 4 times the content of the original drug, preferably not higher than 3 times the content of the original drug. When the amount of the solvent is too high, it is easy to cause a decrease in the coating rate of the original drug; the amount of the solvent (stabilizer) used to dissolve the original drug should be based on the standard of being able to completely dissolve the original drug, or the amount of the solvent (stabilizer) is slightly higher than the amount of the solvent (stabilizer) that can completely dissolve the original drug, such as more than 10% higher.

[0033] The median particle size and the maximum particle size of the microcapsule are measured by the following method:

[0034] Using a Bettersize wet laser particle size analyzer (model BT-2000), 0.5 g of microcapsules were dispersed in 50 mL of water. The circulation and ultrasound were turned on, and the median particle size and maximum particle size of the microcapsules were measured. As is well known to those skilled in the art, for the laser method of detecting and analyzing particle size, even when using the same laser particle size analyzer and measurement conditions, the detection of different batches of samples will result in slight differences in the particle size distribution behavior, thus leading to slight differences in the measurement results, which are generally acceptable to those skilled in the art. Those skilled in the art know that under the same instrument and fixed test conditions, although theoretically the particle size distribution behavior of particles will be relatively fixed, in fact, it is only relatively fixed within a certain range; for example, for the same batch of samples, under the laser particle size analyzer and measurement conditions specified in the present invention, after multiple measurements, theoretically the size of the maximum particle size D90 should be 15 μm, but the actual test results are 13 μm or 14 μm or 16 μm or 17 μm, etc. These different results should also be regarded as the protection scope of the present invention.

[0035] In the present invention, the particle size tests were all carried out using a Bettersize 2000 laser particle size analyzer, and the specific measurement conditions are as follows:

[0036] Test range: 0.02 μm to 2000 μm;

[0037] Light source: single beam and double lenses;

[0038] Test method: wet method;

[0039] Sample concentration: 0.5‰ to 1%;

[0040] Scanning speed: 2 - 3 min / time.

[0041] When the microcapsules are in a liquid medium (for example, forming a suspending agent), they are converted to contain 1 g of microcapsules according to their solid content, and the total dispersion medium is kept at 50 mL, and then the above measurements are carried out.

[0042] Compounds such as abamectin, fluxapyroxad, dimethyl phthalate, tributyl acetylcitrate, and dioctyl phthalate can be determined by conventional chemical characterization means, such as nuclear magnetic resonance, mass spectrometry, high performance liquid chromatography (HPLC), liquid chromatography - mass spectrometry (HPLC - MS), gas chromatography - mass spectrometry, etc. Preferably, HPLC or HPLC - MS is used.

[0043] Preferably, the wall of the microcapsule contains a ureido (-NH-CO-NH-) group. The ureido (-NH-CO-NH-) group in the microcapsule wall is generally formed by reacting an isocyanate group (-NCO) with an amino group (-NH 2) It is obtained by reaction. The ureido group can be determined by conventional chemical characterization means, such as Fourier transform infrared spectroscopy (FT-IR) or carbon-13 solid nuclear magnetic resonance spectroscopy ( 13 C CP / MAS NMR). For example, the Fourier transform infrared spectroscopy (FT-IR) of the microcapsules with intact or disrupted capsule walls is tested; in the infrared spectrum, there is a peak at 2200-2500 cm -1 which is attributed to the C=O vibration peak in the ureido group (-NH-CO-NH-). Generally, the infrared peak of the C=O vibration in the ureido group (-NH-CO-NH-) may have slight differences due to the differences in the structures of the starting compounds. For example, it is located at 2200-2250 cm -1 , or 2250-2300 cm -1 , 2300-2350 cm -1 , 2350-2400 cm -1 , 2400-2450 cm -1 , or 2450-2500 cm -1 , but generally it does not exceed the range of 2200-2500 cm -1 . Again, for example, the carbon-13 solid nuclear magnetic resonance spectroscopy ( 13 C CP / MAS NMR) of the microcapsules with intact or disrupted capsule walls is tested, and it has a characteristic signal peak at 160±15 ppm, preferably at 160±10 ppm. This characteristic signal peak is the characteristic signal peak of the C in the C=O group of the ureido unit. It should be noted that the samples for Fourier transform infrared spectroscopy (FT-IR) or carbon-13 solid nuclear magnetic resonance spectroscopy ( 13 C CP / MAS NMR) determination should be dried samples.

[0044] As a preference of any technical solution of the first aspect of the present invention, the capsule wall of the microcapsule is obtained by reacting raw materials including isocyanate as an oily wall material and polyamine as an aqueous wall material. The -NCO in the isocyanate reacts with the -NH 2 in the polyamine to form a -NH-CO-NH- group.

[0045] It is well known in the art that the isocyanate can be selected from: IPDI (isophorone diisocyanate), TDI (toluene diisocyanate), HDI (hexamethylene diisocyanate), H12MDI (4,4'-dicyclohexylmethane diisocyanate), MDI (diphenylmethane diisocyanate), etc., and the polyamine can be selected from ethylenediamine, triethylenetetramine, ethylenediamine, hexamethylenetetramine, isophorone diamine, etc. The raw materials can be selected according to the requirements of the sustained release, mobility, and stability of the desired microcapsules. For example, MDI reacts with ethylenediamine to form the wall of the microcapsule, or MDI reacts with hexamethylenediamine to form the wall of the microcapsule, or MDI reacts with triethylenetetramine to form the wall of the microcapsule. Preferably, the amount of amino groups (-NH 2 ) in the polyamine is greater than the amount of isocyanate groups (-NCO) in the isocyanate.

[0046] Generally, in the process of preparing the microcapsules, the amount of -NH 2 in the aqueous wall material should not be lower than the amount of -NCO in the oily wall material. Preferably, the amount of -NH 2 in the aqueous wall material is slightly higher than the amount of -NCO in the oily wall material. For example, compared with the amount of -NCO in the oily wall material, the amount of -NH 2 in the aqueous wall material is 5% - 20% more than the amount of -NCO in the oily wall material, or in some cases, compared with the mass of the oily wall material, the amount of the aqueous wall material is 5% - 20% more than the mass of the oily wall material, so that the oily wall material can react fully.

[0047] In the process of preparing the microcapsules, to ensure the encapsulation rate of the original drug and the thickness and toughness of the wall of the microcapsule, based on the amount of the original drug, the amount of the oily wall material is generally not lower than 20% of the total mass of the original drug, preferably not lower than 30% of the total mass of the original drug. As the amount of the original drug increases, the amount of the oily wall material should also increase. However, the amount of the oily wall material is not the more the better. Excessive amounts of the oily wall material and the aqueous wall material will also cause the wall of the microcapsule to be too thick or empty microcapsules to appear. Generally, the amount of the oily wall material is not higher than 60% of the total mass of the original drug, and preferably, it is not higher than 50% of the total mass of the original drug.

[0048] As a preference of any technical solution of the first aspect of the present invention, the content of abamectin in the microcapsules is 0.05 - 0.20 g / g.

[0049] As a preference of any technical solution of the first aspect of the present invention, the content of fluopyram in the microcapsules is 0.10 - 0.30 g / g.

[0050] It should be noted that due to the influence of factors such as the solubility of abamectin and fluxapyroxad technical materials and the dosage of stabilizers, as well as the requirements for the final release and mobility of the microcapsules in the soil, within the above content range of the technical materials, microcapsules with better persistence and mobility in the soil can be comprehensively obtained.

[0051] As a preference of any technical solution of the first aspect of the present invention, the content (by weight) ratio of the first active ingredient to the second active ingredient is A:B, where

[0052] The A can be selected from any one of the following numerical ranges or any numerical value: (0.1 - 20), (0.5 - 20), (1 - 20), (3 - 20), (4 - 20), (5 - 20), (7 - 20), (9 - 20), (10 - 20), (12 - 20), (14 - 20), (16 - 20), (0.1 - 15), (0.5 - 15), (1 - 15), (3 - 15), (4 - 15), (5 - 15), (7 - 15), (9 - 15), (10 - 15), (12 - 15), (14 - 15), (0.1 - 10), (0.5 - 10), (1 - 10), (3 - 10), (4 - 10), (5 - 10), (7 - 10), (9 - 10), (0.1 - 8), (0.5 - 8), (1 - 8), (3 - 8), (4 - 8), (5 - 8), (7 - 8), (0.1 - 7), (0.5 - 7), (1 - 7), (3 - 7), (4 - 7), (5 - 7), (0.1 - 3), (0.5 - 3), (1 - 3), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10;

[0053] B can be selected from any one of the following numerical ranges or any numerical value: (0.1 - 20), (0.5 - 20), (1 - 20), (3 - 20), (4 - 20), (5 - 20), (7 - 20), (9 - 20), (10 - 20), (12 - 20), (14 - 20), (16 - 20), (0.1 - 15), (0.5 - 15), (1 - 15), (3 - 15), (4 - 15), (5 - 15), (7 - 15), (9 - 15), (10 - 15), (12 - 15), (14 - 15), (0.1 - 10), (0.5 - 10), (1 - 10), (3 - 10), (4 - 10), (5 - 10), (7 - 10), (9 - 10), (0.1 - 8), (0.5 - 8), (1 - 8), (3 - 8), (4 - 8), (5 - 8), (7 - 8), (0.1 - 7), (0.5 - 7), (1 - 7), (3 - 7), (4 - 7), (5 - 7), (0.1 - 3), (0.5 - 3), (1 - 3), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

[0054] For example, the weight ratio of abamectin to fluxapyroxad in the microcapsule is (1 - 20):(1 - 20). Further, the weight ratio of abamectin to fluxapyroxad in the microcapsule is (1 - 10):(1 - 15). Still further, the weight ratio of abamectin to fluxapyroxad in the microcapsule is (3 - 10):(3 - 15).

[0055] More preferably, the weight ratio of abamectin to fluxapyroxad in the microcapsule is 3:(4 - 12); preferably 3:(5 - 10); most preferably 3:(6 - 9).

[0056] As a preference for any technical solution of the first aspect of the present invention, the content (by weight) ratio of dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate in the stabilizer is C:D:E, where

[0057] C can be any one of the following value ranges or any value: selected from (1 - 30), (3 - 30), (4 - 30), (5 - 30), (7 - 30), (9 - 30), (10 - 30), (12 - 30), (14 - 30), (16 - 30), (20 - 30), (1 - 25), (3 - 25), (4 - 25), (5 - 25), (7 - 25), (9 - 25), (10 - 25), (12 - 25), (14 - 25), (16 - 25), (20 - 25), (1 - 20), (3 - 20), (4 - 20), (5 - 20), (7 - 20), (9 - 20), (10 - 20), (12 - 20), (14 - 20), (15 - 20), (16 - 20), (1 - 15), (3 - 15), (4 - 15), (5 - 15), (7 - 15), (9 - 15), (10 - 15), (12 - 15), (14 - 15), (1 - 10), (3 - 10), (4 - 10), (5 - 10), (7 - 10), (9 - 10), (1 - 8), (3 - 8), (4 - 8), (5 - 8), (7 - 8), (1 - 7), (3 - 7), (4 - 7), (5 - 7), (1 - 5), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20;

[0058] D can be any one of the following value ranges or any value: selected from (1 - 25), (3 - 25), (4 - 25), (5 - 25), (7 - 25), (9 - 25), (10 - 25), (12 - 25), (14 - 25), (16 - 25), (20 - 25), (1 - 20), (3 - 20), (4 - 20), (5 - 20), (7 - 20), (9 - 20), (10 - 20), (12 - 20), (14 - 20), (15 - 20), (16 - 20), (1 - 15), (3 - 15), (4 - 15), (5 - 15), (7 - 15), (9 - 15), (10 - 15), (12 - 15), (14 - 15), (1 - 10), (3 - 10), (4 - 10), (5 - 10), (7 - 10), (9 - 10), (1 - 8), (3 - 8), (4 - 8), (5 - 8), (7 - 8), (1 - 7), (3 - 7), (4 - 7), (5 - 7), (1 - 5), (3 - 5), (1 - 4), (3 - 4), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10;

[0059] E can be any one selected from the following numerical ranges or any numerical value: (1-25), (3-25), (4-25), (5-25), (7-25), (9-25), (10-25), (12-25), (14-25), (16-25), (20-25), (1-20), (3-20), (4-20), (5-20), (7-20), (9-20), (10-20), (12-20), (14-20), (15-20), (16-20), (1-15), (3-15), (4-15), (5-15), (7-15), (9-15), (10-15), (12-15), (14-15), (1-10), (3-10), (4-10), (5-10), (7-10), (9-10), (1-8), (3-8), (4-8), (5-8), (7-8), (1-7), (3-7), (4-7), (5-7), (1-5), (3-5), (1-4), (3-4), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

[0060] For example, the weight ratio of dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate in the stabilizer is (1-30):(1-25):(1-25). Further, the weight ratio of dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate in the stabilizer is (1-25):(1-15):(1-15). Still further, the weight ratio of dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate in the stabilizer is (10-20):(1-10):(1-10).

[0061] As a preference of any technical solution of the first aspect of the present invention, the weight ratio of dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate in the microcapsule is (1-25):(1-15):1; preferably (1-20):(1-8):1; more preferably (1-10):(1-5):1; most preferably (1-5):(1-4):1.

[0062] As a preferred solution of the technical solution of the first aspect of the present invention, the second aspect of the present invention provides a microcapsule containing abamectin and fluxapyroxad. The microcapsule contains abamectin, fluxapyroxad, dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate.

[0063] The median particle size D50 of the microcapsule is 0.6-5.0 μm; preferably 0.8-4.0 μm; more preferably 1.0-3.0 μm; most preferably 1.0-2.0 μm.

[0064] The maximum particle size D90 of the microcapsules is 1.0 to 15.0 μm; preferably 1.2 to 12.0 μm; more preferably 2.0 to 6.0 μm; most preferably 2.5 to 5.0 μm;

[0065] By weight, the microcapsules contain:

[0066]

[0067] As a preference for any technical solution of the second aspect of the present invention, by weight, the microcapsules contain:

[0068]

[0069] The measurement methods for the particle size of the microcapsules and the weight percentages of various substances are the same as those described above and will not be elaborated here.

[0070] Preferably, the wall of the microcapsules contains ureido (-NH-CO-NH-) groups; the ureido (-NH-CO-NH-) groups in the wall of the microcapsules are generally obtained by reacting isocyanate groups (-NCO) with amino groups (-NH 2 ) groups, and the ureido groups can be determined by conventional chemical characterization means, such as Fourier transform infrared spectroscopy (FT-IR) or carbon-13 solid nuclear magnetic resonance spectroscopy ( 13 C CP / MAS NMR). For example, test the Fourier transform infrared spectroscopy (FT-IR) of the microcapsules with the wall intact or the wall damaged; in the infrared spectrum, there is a peak in the range of 2200 - 2500 cm -1 which is attributed to the C=O vibration peak of the ureido group (-NH-CO-NH-). Generally, the infrared peak of the C=O vibration peak in the ureido group (-NH-CO-NH-) may have slight differences due to the differences in the structures of the starting compounds, such as being located at 2200 - 2250 cm -1 , or 2250 - 2300 cm -1 , 2300 - 2350 cm -1 , 2350 - 2400 cm -1 , 2400 - 2450 cm -1 , or 2450 - 2500 cm -1 , but generally does not exceed the range of 2200 - 2500 cm -1 . Again, for example, test the carbon-13 solid nuclear magnetic resonance spectroscopy of the microcapsules with the wall intact or the wall damaged ( 13C CP / MAS NMR), has a characteristic signal peak at 160 ± 15 ppm, preferably at 160 ± 10 ppm. This characteristic signal peak is the characteristic signal peak of C in the C=O group of the urea unit. It should be noted that the sample for Fourier transform infrared spectroscopy (FT-IR) or carbon-13 solid nuclear magnetic resonance spectroscopy ( 13 The sample for C CP / MAS NMR determination should be a dried sample.

[0071] As a preference for any technical solution of the second aspect of the present invention, the wall of the microcapsule is obtained by reacting raw materials including isocyanate as an oil-based wall material and polyamine as an aqueous wall material. -NCO in the isocyanate reacts with -NH 2 in the polyamine to form a -NH-CO-NH- group.

[0072] It is well known in the art that the isocyanate can be selected from: IPDI (isophorone diisocyanate), TDI (toluene diisocyanate), HDI (hexamethylene diisocyanate), H12MDI (4,4'-dicyclohexylmethane diisocyanate), MDI (diphenylmethane diisocyanate), etc., and the polyamine can be selected from ethylenediamine, triethylenetetramine, ethylenediamine, hexamethylenetetramine, isophorone diamine, etc. The raw materials can be selected according to the requirements of the sustained release, mobility, and stability of the required microcapsules. For example, MDI reacts with ethylenediamine to form the wall of the microcapsule, or MDI reacts with hexamethylenediamine to form the wall of the microcapsule, or MDI reacts with triethylenetetramine to form the wall of the microcapsule.

[0073] Usually, in the process of preparing the microcapsule, the amount of -NH 2 in the aqueous wall material should not be lower than the amount of -NCO in the oil-based wall material. Preferably, the amount of -NH 2 in the aqueous wall material is slightly higher than the amount of -NCO in the oil-based wall material. For example, compared with the amount of -NCO in the oil-based wall material, the amount of -NH 2 in the aqueous wall material is 5% - 20% more than the amount of -NCO in the oil-based wall material, or in some cases, compared with the mass of the oil-based wall material, the amount of the aqueous wall material is 5% - 20% more than the mass of the oil-based wall material, so that the oil-based wall material can fully react.

[0074] During the preparation of microcapsules, to ensure the encapsulation rate of the original drug and the thickness and toughness of the capsule wall, the amount of the oily wall material is based on the amount of the original drug. Generally, the dosage of the oily wall material is not less than 20% of the total mass of the original drug, preferably not less than 30% of the total mass of the original drug. As the amount of the original drug increases, the amount of the oily wall material should also increase. However, the dosage of the oily wall material is not the more the better. Excessive amounts of the oily wall material and the aqueous wall material will also cause the capsule wall to be too thick or empty capsules to appear. Generally, the dosage of the oily wall material is not higher than 60% of the total mass of the original drug, preferably not higher than 50% of the total mass of the original drug.

[0075] [Preparation method of microcapsules containing abamectin and fluxapyroxad]

[0076] The third aspect of the present invention provides a preparation method of the microcapsules according to any one of the technical solutions of the first aspect or the second aspect, including:

[0077] Configuration of the aqueous phase component, and the aqueous phase component contains an emulsifying dispersant and an antifoaming agent;

[0078] Configuration of the oil phase component, and the oil phase component contains abamectin and fluxapyroxad dissolved in a mixed solvent of dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate, and an oily wall material;

[0079] Emulsification, contacting and mixing the configured oil phase component with the aqueous phase component and shearing and stirring to obtain an oil-in-water emulsion;

[0080] Capsule wall reaction, mixing the aqueous wall material with the emulsion obtained by emulsification, and carrying out interfacial polymerization to form a capsule wall to obtain microcapsules containing active ingredients, continuously accompanied by a stirring operation;

[0081] Heat preservation and curing.

[0082] The schematic diagram of the preparation principle of the microcapsules is as Figure 1 shown.

[0083] At this time, the obtained microcapsules are in a liquid medium, and it can be determined according to actual needs whether it is necessary to separate the microcapsules in the liquid medium. For example, if it is necessary to prepare a microcapsule suspension, the microcapsules in the liquid medium can be directly used for the next step;

[0084] If it is necessary to prepare microcapsule powder, the microcapsules in the liquid medium can be dried to obtain dry microcapsules. The drying treatment method can adopt freeze-drying, spray-drying and other methods. Specifically, for example:

[0085] i. Separating the microcapsules from the liquid medium by centrifugation

[0086] Centrifuging at 10,000 rpm for 5 minutes, discarding the supernatant, and washing with deionized water to obtain the microcapsules;

[0087] ii. Then freeze-dry the obtained microcapsules to obtain freeze-dried microcapsule powder

[0088] The freeze-dried microcapsule powder is obtained by freeze-drying at -70°C for 8 hours.

[0089] As a preference of any technical solution of the third aspect of the present invention, the oily wall material can be isocyanate, and the isocyanate can be selected from: IPDI, TDI, HDI, H12MDI, MDI, etc.

[0090] As a preference of any technical solution of the third aspect of the present invention, the aqueous wall material can be polyamine, and the polyamine can be selected from diamine, triethylenetetramine, ethylenediamine, hexamethylenetetramine, isophoronediamine, etc.

[0091] During the preparation process, microcapsules with different particle size ranges can be obtained by adjusting the shear speed in the emulsification step. For example, when it is desired to obtain microcapsules with a lower median particle size (D50) and a lower maximum particle size (D90), a higher shear speed can be adopted; while when it is desired to obtain microcapsules with a higher median particle size (D50) and a higher maximum particle size (D90), a lower shear speed can be adopted. In the experiment, the shear speed can be specifically adjusted according to this principle to obtain microcapsules with a median particle size (D50) and a maximum particle size (D90) that meet the requirements of the present invention; in the present invention, the shear speed is generally not less than 10000 rpm, more preferably not less than 12000 rpm; the shear speed is generally not higher than 17000 rpm, preferably not higher than 15000 rpm.

[0092] As a preference of any technical solution of the third aspect of the present invention, the temperature of heat preservation and curing is generally between 60 and 70°C. Considering the improvement of the completeness of the polymerization reaction, the temperature of heat preservation and curing can be selected at a relatively low level within the range of 60 to 65°C; considering the improvement of the polymerization reaction speed, the temperature of heat preservation and curing can be selected at a relatively high level within the range of 65 to 70°C.

[0093] As a preference of any technical solution of the third aspect of the present invention, the time of heat preservation and curing is generally between 2 and 4 hours. Considering the improvement of the toughness of the microcapsule wall material, the time of heat preservation and curing can be between 2 and 3 hours; considering the improvement of the microcapsule encapsulation rate, the time of heat preservation and curing can be between 3 and 4 hours.

[0094] The present invention also provides the application of the microcapsules containing abamectin and fluxapyroxad described in any one of the first aspect or the second aspect of the present invention, or the microcapsules containing abamectin and fluxapyroxad prepared by the preparation method described in any one of the third aspect in pesticides.

[0095] Preferably, the microcapsules containing abamectin and fluxapyroxad are used for killing nematodes and / or sterilizing. Since nematodes are usually located at the roots of plants, after the microcapsules of the present invention are applied to the soil body, the microcapsules have good vertical mobility in the soil and are easy to reach the diseased roots of plants and slowly release the active ingredients. Therefore, the microcapsule suspension of the present invention has a good effect on preventing and killing nematodes at the roots of plants.

[0096] [Microcapsule suspension containing abamectin and fluxapyroxad]

[0097] It should be noted that usually in the process of preparing a microcapsule suspension, first, a microcapsule liquid containing microcapsules is obtained, and then other reagents are added to the microcapsule liquid to obtain a microcapsule suspension with additional specific properties. For example, when it is required that the microcapsule suspension has improved anti-freezing properties, an anti-freezing agent is added to the microcapsule liquid; when it is required that the microcapsule suspension has enhanced storage stability, a thickening agent is added to the microcapsule liquid; when it is required that the microcapsule suspension has improved anti-corrosion properties, a preservative is added to the microcapsule liquid. Therefore, the preparation of microcapsules can be regarded as a part of the process of preparing a microcapsule suspension, and microcapsules can also be regarded as intermediate products obtained in the process of preparing a microcapsule suspension. Therefore, some definitions, explanations, and the functions and effects of reagents in the microcapsule part and the microcapsule suspension part are generally the same in principle.

[0098] The fourth aspect of the present invention provides a microcapsule suspension containing abamectin and fluxapyroxad, comprising microcapsules dispersed in an aqueous liquid medium, wherein the microcapsules contain the technical material and a stabilizer;

[0099] The technical material contains a first active ingredient and a second active ingredient; the first active ingredient contains abamectin, and the second active ingredient contains fluxapyroxad;

[0100] The stabilizer contains dimethyl phthalate, tributyl acetylcitrate, and dioctyl phthalate;

[0101] The median particle size D50 of the microcapsules is 0.6 - 5.0 μm; preferably 0.8 - 4.0 μm; more preferably 1.0 - 3.0 μm; most preferably 1.0 - 2.0 μm;

[0102] The maximum particle size D90 of the microcapsules is 1.0 - 15.0 μm; preferably 1.2 - 12.0 μm; more preferably 2.0 - 6.0 μm; most preferably 2.5 - 5.0 μm;

[0103] For example, the median particle size D50 of the microcapsules is 0.6 - 5.0 μm, and the maximum particle size D90 is 1.0 - 15.0 μm; or preferably, the median particle size D50 of the microcapsules is 0.8 - 4.0 μm, and the maximum particle size D90 is 1.2 - 12.0 μm; or preferably, the median particle size D50 of the microcapsules is 1.0 - 3.0 μm, and the maximum particle size D90 is 2.0 - 6.0 μm; or preferably, the median particle size D50 of the microcapsules is 1.0 - 2.0 μm, and the maximum particle size D90 is 2.5 - 5.0 μm;

[0104] Among them, the percentage (wt%) of abamectin in the suspending agent is 1 - 20 wt%, and more preferably 1 - 10 wt%;

[0105] The percentage (wt%) of fluxapyroxad in the suspending agent is 1 - 20 wt%, and more preferably 2 - 15 wt%.

[0106] Among them, based on the total weight of the microcapsule suspending agent being 100%.

[0107] As a preference of any technical solution of the fourth aspect of the present invention, the percentage (wt%) of the sum of the weights of abamectin and fluxapyroxad in the suspending agent can be any value taken from any of the following numerical ranges or within the ranges:

[0108] 2 - 40 wt%, 2 - 35 wt%, 2 - 30 wt%, 2 - 25 wt%, 2 - 20 wt%, 2 - 15 wt%, 2 - 10 wt%, 2 - 5 wt%;

[0109] 5 - 40 wt%, 5 - 35 wt%, 5 - 30 wt%, 5 - 25 wt%, 5 - 20 wt%, 5 - 15 wt%, 5 - 10 wt%;

[0110] 10 - 40 wt%, 10 - 35 wt%, 10 - 30 wt%, 10 - 25 wt%, 10 - 20 wt%, 10 - 15 wt%;

[0111] 20 - 40 wt%, 20 - 35 wt%, 20 - 30 wt%, 20 - 25 wt%;

[0112] 30 - 40 wt%, 30 - 35 wt%.

[0113] As a preference of any technical solution of the fourth aspect of the present invention, the percentage (wt%) of the sum of the weights of abamectin and fluxapyroxad in the suspending agent is 5 - 25 wt%, and more preferably 5 - 15 wt%.

[0114] Preferably, for any technical solution of the fourth aspect of the present invention, the percentage by weight (wt%) of abamectin in the suspending agent can be any value taken from any of the following numerical ranges or within the ranges:

[0115] 1-20 wt%, 1-18 wt%, 1-15 wt%, 1-12 wt%, 1-10 wt%, 1-8 wt%, 1-7 wt%, 1-5 wt%, 1-3 wt%, 1-2 wt%;

[0116] 2-20 wt%, 2-18 wt%, 2-15 wt%, 2-12 wt%, 2-10 wt%, 2-8 wt%, 2-7 wt%, 2-5 wt%, 2-3 wt%;

[0117] 3-20 wt%, 3-18 wt%, 3-15 wt%, 3-12 wt%, 3-10 wt%, 3-8 wt%, 3-7 wt%, 3-5 wt%;

[0118] 4-20 wt%, 4-18 wt%, 4-15 wt%, 4-12 wt%, 4-10 wt%, 4-8 wt%, 4-7 wt%, 4-5 wt%;

[0119] 5-20 wt%, 5-18 wt%, 5-15 wt%, 5-12 wt%, 5-10 wt%, 5-8 wt%, 5-7 wt%;

[0120] 7-20 wt%, 7-18 wt%, 7-15 wt%, 7-12 wt%, 7-10 wt%, 7-8 wt%;

[0121] 10-20 wt%, 10-18 wt%, 10-15 wt%, 10-12 wt%;

[0122] 12-20 wt%, 12-18 wt%, 12-15 wt%;

[0123] 15-20 wt%, 15-18 wt%.

[0124] Preferably, for any technical solution of the fourth aspect of the present invention, the percentage by weight (wt%) of fluxapyroxad in the suspending agent can be any value taken from any of the following numerical ranges or within the ranges:

[0125] 1-20 wt%, 1-18 wt%, 1-15 wt%, 1-12 wt%, 1-10 wt%, 1-8 wt%, 1-7 wt%, 1-5 wt%, 1-3 wt%, 1-2 wt%;

[0126] 2 - 20 wt%, 2 - 18 wt%, 2 - 15 wt%, 2 - 12 wt%, 2 - 10 wt%, 2 - 8 wt%, 2 - 7 wt%, 2 - 5 wt%, 2 - 3 wt%;

[0127] 3 - 20 wt%, 3 - 18 wt%, 3 - 15 wt%, 3 - 12 wt%, 3 - 10 wt%, 3 - 8 wt%, 3 - 7 wt%, 3 - 5 wt%;

[0128] 4 - 20 wt%, 4 - 18 wt%, 4 - 15 wt%, 4 - 12 wt%, 4 - 10 wt%, 4 - 8 wt%, 4 - 7 wt%, 4 - 5 wt%;

[0129] 5 - 20 wt%, 5 - 18 wt%, 5 - 15 wt%, 5 - 12 wt%, 5 - 10 wt%, 5 - 8 wt%, 5 - 7 wt%;

[0130] 7 - 20 wt%, 7 - 18 wt%, 7 - 15 wt%, 7 - 12 wt%, 7 - 10 wt%, 7 - 8 wt%;

[0131] 10 - 20 wt%, 10 - 18 wt%, 10 - 15 wt%, 10 - 12 wt%;

[0132] 12 - 20 wt%, 12 - 18 wt%, 12 - 15 wt%;

[0133] 15 - 20 wt%, 15 - 18 wt%.

[0134] As a preference of any technical solution of the fourth aspect of the present invention, the weight ratio of abamectin to fluxapyroxad in the suspending agent is 3:(4 - 12); preferably 3:(5 - 10); most preferably 3:(6 - 9).

[0135] As a preference of any technical solution of the fourth aspect of the present invention, the total weight of the stabilizers in the suspending agent generally accounts for 20 - 40 wt%, preferably 20 - 30 wt%. When the content of the stabilizer is low, it is not sufficient to dissolve the technical material, resulting in a low coating rate; and from the perspective of dissolving the technical material as much as possible, when the content of the technical material increases, the content of the stabilizer also increases accordingly; but when the content of the stabilizer is too high, oil droplets will appear in the shearing step, which will also cause the problem of low coating rate of the technical material.

[0136] As a preference of any technical solution of the fourth aspect of the present invention, the percentage of dioctyl phthalate in the suspending agent (wt%) can be any value taken from any of the following numerical ranges or within the range:

[0137] 2 - 20 wt%, 2 - 18 wt%, 2 - 15 wt%, 2 - 12 wt%, 2 - 10 wt%, 2 - 8 wt%, 2 - 7 wt%, 2 - 5 wt%, 2 - 3 wt%;

[0138] 3 - 20 wt%, 3 - 18 wt%, 3 - 15 wt%, 3 - 12 wt%, 3 - 10 wt%, 3 - 8 wt%, 3 - 7 wt%, 3 - 5 wt%;

[0139] 4 - 20 wt%, 4 - 18 wt%, 4 - 15 wt%, 4 - 12 wt%, 4 - 10 wt%, 4 - 8 wt%, 4 - 7 wt%, 4 - 5 wt%;

[0140] 5 - 20 wt%, 5 - 18 wt%, 5 - 15 wt%, 5 - 12 wt%, 5 - 10 wt%, 5 - 8 wt%, 5 - 7 wt%;

[0141] 7 - 20 wt%, 7 - 18 wt%, 7 - 15 wt%, 7 - 12 wt%, 7 - 10 wt%, 7 - 8 wt%;

[0142] 10 - 20 wt%, 10 - 18 wt%, 10 - 15 wt%, 10 - 12 wt%;

[0143] 12 - 20 wt%, 12 - 18 wt%, 12 - 15 wt%;

[0144] 15 - 20 wt%, 15 - 18 wt%.

[0145] As a preference of any technical solution of the fourth aspect of the present invention, the percentage of dioctyl phthalate in the suspending agent is 3 - 20 wt%; Considering from the economic perspective, the percentage of dioctyl phthalate in the suspending agent is 3 - 10 wt%.

[0146] As a preference of any technical solution of the fourth aspect of the present invention, the percentage of dimethyl phthalate in the suspending agent (wt%) can be any value taken from any of the following numerical ranges or within the ranges:

[0147] 5 - 25 wt%, 5 - 20 wt%, 5 - 18 wt%, 5 - 15 wt%, 5 - 12 wt%, 5 - 10 wt%, 5 - 8 wt%, 5 - 7 wt%;

[0148] 7 - 25 wt%, 7 - 20 wt%, 7 - 18 wt%, 7 - 15 wt%, 7 - 12 wt%, 7 - 10 wt%, 7 - 8 wt%;

[0149] 10 - 25 wt%, 10 - 20 wt%, 10 - 18 wt%, 10 - 15 wt%, 10 - 12 wt%;

[0150] 12 - 25 wt%, 12 - 20 wt%, 12 - 18 wt%, 12 - 15 wt%;

[0151] 15 - 25 wt%, 15 - 20 wt%, 15 - 18 wt%.

[0152] 20 - 25 wt%.

[0153] As a preference of any technical solution of the fourth aspect of the present invention, the content percentage of dimethyl phthalate in the suspending agent is 10 - 20 wt%; preferably 15 - 20 wt%.

[0154] As a preference of any technical solution of the fourth aspect of the present invention, the content percentage of tributyl acetylcitrate in the suspending agent (wt%) can be any value taken from any of the following numerical ranges or within the ranges:

[0155] 3 - 12 wt%, 3 - 10 wt%, 3 - 8 wt%, 3 - 7 wt%, 3 - 5 wt%;

[0156] 4 - 12 wt%, 4 - 10 wt%, 4 - 8 wt%, 4 - 7 wt%, 4 - 5 wt%;

[0157] 5 - 12 wt%, 5 - 10 wt%, 5 - 8 wt%, 5 - 7 wt%;

[0158] 7 - 12 wt%, 7 - 10 wt%, 7 - 8 wt%;

[0159] 10 - 12 wt%.

[0160] As a preference of any technical solution of the fourth aspect of the present invention, the content percentage of tributyl acetylcitrate in the suspending agent is 3 - 10 wt%; preferably 3 - 8 wt%.

[0161] Preferably, the wall of the microcapsule contains ureido (-NH-CO-NH-) groups. The ureido (-NH-CO-NH-) groups in the microcapsule wall are generally obtained by the reaction of isocyanate groups (-NCO) with amino groups (-NH 2 ) and the ureido groups can be determined by conventional chemical characterization means, such as Fourier transform infrared spectroscopy (FT-IR) or carbon-13 solid state nuclear magnetic resonance spectroscopy ( 13 C CP / MAS NMR). For example, test the Fourier transform infrared spectroscopy (FT-IR) of the microcapsules with intact or damaged walls; in the infrared spectrum, the absorption band located at 2200 - 2500 cm -1There is a peak attributed to the C=O vibration peak in the ureido group (-NH-CO-NH-). Generally, the infrared peak of the C=O vibration peak in the ureido group (-NH-CO-NH-) will have slight differences due to the differences in the structures of the raw material compounds. For example, it is located at 2200-2250 cm -1 , or 2250-2300 cm -1 , 2300-2350 cm -1 , 2350-2400 cm -1 , 2400-2450 cm -1 , or 2450-2500 cm -1 , but generally it will not exceed the range of 2200-2500 cm -1 . For another example, when testing the solid carbon-13 nuclear magnetic resonance spectrum ( 13 C CP / MAS NMR) of the microcapsules with intact or damaged capsule walls, there is a characteristic signal peak at 160±15 ppm, preferably at 160±10 ppm. This characteristic signal peak is the characteristic signal peak of C in the C=O group of the ureido unit.

[0162] As a preference for any technical solution of the fourth aspect of the present invention, the capsule wall of the microcapsule is obtained by reacting raw materials including an isocyanate as an oily wall material and a polyamine as an aqueous wall material. The -NCO in the isocyanate reacts with the -NH 2 in the polyamine to form an -NH-CO-NH- group.

[0163] It is well known in the art that the isocyanate can be selected from: IPDI (isophorone diisocyanate), TDI (toluene diisocyanate), HDI (hexamethylene diisocyanate), H12MDI (4,4'-dicyclohexylmethane diisocyanate), MDI (diphenylmethane diisocyanate), etc., and the polyamine can be selected from ethylenediamine, triethylenetetramine, ethylenediamine, hexamethylenetetramine, isophoronediamine, etc. The raw materials can be selected according to the requirements of the sustained release, mobility, and stability of the required microcapsules. For example, MDI reacts with ethylenediamine to form the capsule wall of the microcapsule, or MDI reacts with hexamethylenediamine to form the capsule wall of the microcapsule, or MDI reacts with triethylenetetramine to form the capsule wall of the microcapsule.

[0164] Generally, in the process of preparing the microcapsule, the amount of substance of -NH 2 in the aqueous wall material should not be lower than the amount of substance of -NCO in the oily wall material. Preferably, the amount of substance of -NH 2 in the aqueous wall material is slightly higher than the amount of substance of -NCO in the oily wall material. For example, compared with the amount of substance of -NCO in the oily wall material, the amount of substance of -NH 2The amount of substance is 5% - 20% more than the amount of -NCO in the oily wall material, or in some cases, the amount of the aqueous wall material is 5% - 20% more than the mass of the oily wall material compared to the mass of the oily wall material, so that the oily wall material can fully react.

[0165] During the preparation of the microcapsules, to ensure the encapsulation rate of the original drug and the thickness and toughness of the capsule wall, the amount of the oily wall material is based on the amount of the original drug. Generally, the dosage of the oily wall material is not less than 20% of the total mass of the original drug, preferably not less than 30% of the total mass of the original drug. As the amount of the original drug increases, the amount of the oily wall material should also increase. However, the dosage of the oily wall material is not necessarily the more the better. Excessive amounts of the oily wall material and the aqueous wall material will also cause the capsule wall to be too thick or empty capsules to appear. Usually, the dosage of the oily wall material is not higher than 60% of the total mass of the original drug, and preferably, not higher than 50% of the total mass of the original drug.

[0166] As a preference for any technical solution of the fourth aspect of the present invention, the dosage of the oily wall material during the preparation of the suspending agent accounts for 3 - 10%; as the amount of the original drug increases, the amount of the oily wall material should also increase. Preferably, during the preparation of the suspending agent, -NH 2 The amount of substance should be slightly higher than the amount of -NCO in the oily wall material, so that the oily wall material can fully react.

[0167] As a preference for any technical solution of the fourth aspect of the present invention, the weight percentage of the microcapsules in the suspending agent is 10 - 70 wt%; further preferably, the weight percentage of the microcapsules in the suspending agent is 20 - 60 wt%; further preferably, the weight percentage of the microcapsules in the suspending agent is 30 - 50 wt%.

[0168] Among them, the weight percentage of the microcapsules in the suspending agent can be obtained by the following method:

[0169] i. Separate the microcapsules from the suspension by centrifugation:

[0170] Centrifuge at 10000 rpm for 5 min, discard the supernatant, and wash with deionized water to obtain the microcapsules;

[0171] ii. Then freeze-dry the obtained microcapsules to obtain microcapsule freeze-dried powder:

[0172] Freeze-dry at -70°C for 8 h to obtain the microcapsule freeze-dried powder;

[0173] iii. Weigh the weight of the microcapsule freeze-dried powder and calculate the percentage content of the microcapsule freeze-dried powder in the suspension.

[0174] Preferably, for any technical solution of the fourth aspect of the present invention, the suspension further contains an emulsifying dispersant. The emulsifying dispersant can improve the surface tension between phases in the emulsifying system, enhance the emulsifying and dispersing property of the system, and make the system more uniform and stable.

[0175] The emulsifying dispersant is selected from one or more of sodium lignosulfonate or calcium lignosulfonate, alkylaryl polyoxyethylene polyoxypropylene ether, sodium naphthol sulfonate formaldehyde condensate, alkylphenol polyoxyethylene polyoxypropylene ether, styrene maleic anhydride, methylnaphthalene sulfonic acid formaldehyde condensate, castor oil ethylene oxide adduct, alkylphenol polyoxyethylene polyoxypropylene ether, alkyl-diethylene glycol ether-sulfonate, and sodium N-methyl-oleoyl-taurine.

[0176] The weight percentage (wt%) of the emulsifying dispersant based on the suspending agent is 0.1 - 10 wt%; preferably 0.5 - 5 wt%.

[0177] Preferably, for any technical solution of the fourth aspect of the present invention, the suspension further contains an antifoaming agent.

[0178] The antifoaming agent is selected from one or more of silicone SAG1522, silicones, silicone oils, fatty alcohols with 8 - 10 carbon atoms, phosphate esters, saturated fatty acids with 10 - 20 carbon atoms (such as capric acid), and amides.

[0179] The weight percentage (wt%) of the antifoaming agent based on the suspending agent is 0.1 - 10 wt%; preferably 0.5 - 5 wt%.

[0180] Preferably, for any technical solution of the fourth aspect of the present invention, the suspension further contains an antifreeze agent. The antifreeze agent can improve the antifreeze ability of the suspension system and effectively prevent the condensation of ice crystals in the suspension system or the dissolution of the condensed ice crystals in the solution system.

[0181] The antifreeze agent is selected from, but not limited to, one or more of ethanol, isopropanol, ethylene glycol, propylene glycol, glycerol, diethylene glycol, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, and urea.

[0182] The weight percentage (wt%) of the antifreeze agent based on the suspending agent is 0.1 - 10 wt%; preferably 0.5 - 5 wt%.

[0183] Preferably, for any technical solution of the fourth aspect of the present invention, the suspension further contains a preservative.

[0184] The preservative is selected from, but not limited to, one or more of sodium benzoate, benzoic acid, Kathon, potassium sorbate, sorbic acid, or sulfites.

[0185] The weight percentage (wt%) of the preservative based on the suspending agent is 0.1 - 5 wt%; preferably 0.5 - 2 wt%.

[0186] Preferably, for any technical solution of the fourth aspect of the present invention, the suspension further contains a thickener. The thickener can increase the viscosity of the solution mixing system and enhance the storage stability of the suspension emulsion.

[0187] The thickener is selected from, but not limited to, one or more of clay, rock powder, chalk, quartz, clay, montmorillonite, sodium sulfate, silica, diatomaceous earth, pumice, gypsum, talc, bentonite, kaolin, attapulgite, light calcium carbonate, clay, magnesium aluminum silicate, activated clay, silica white, ammonium sulfate, benzofuran resin, superphosphate, alumina, calcite, marble, pumice, xanthan gum, gum arabic, gelatin or cyclodextrin.

[0188] The weight percentage (wt%) of the thickener in the suspending agent is 1-20 wt%; preferably 2-10 wt%.

[0189] As a preferred technical solution of the fourth aspect of the present invention, the fifth aspect of the present invention provides a microcapsule suspension containing abamectin and fluxapyroxad, including microcapsules dispersed in an aqueous liquid medium, and the microcapsules contain abamectin, fluxapyroxad, dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate;

[0190] The median particle size D50 of the microcapsules is 0.6-5.0 μm; preferably 0.8-4.0 μm; more preferably 1.0-3.0 μm; most preferably 1.0-2.0 μm;

[0191] The maximum particle size D90 of the microcapsules is 1.0-15.0 μm; preferably 1.2-12.0 μm; more preferably 2.0-6.0 μm; most preferably 2.5-5.0 μm;

[0192] By weight percentage (wt%), the suspending agent contains:

[0193]

[0194] Preferably, for any technical solution of the fifth aspect of the present invention, it further contains:

[0195] Antifreeze 0.1-10 wt%

[0196] Thickener 1-20 wt%.

[0197] Preferably, for any technical solution of the fifth aspect of the present invention, it further contains:

[0198] Preservative 0.1-5 wt%.

[0199] Preferably, by weight percentage (wt%), the suspending agent contains:

[0200]

[0201] Preferably, the wall of the microcapsule contains a ureido group (-NH-CO-NH-). The ureido group (-NH-CO-NH-) in the microcapsule wall is generally obtained by reacting an isocyanate group (-NCO) with an amino group (-NH 2 ). The ureido group can be determined by conventional chemical characterization means, such as Fourier transform infrared spectroscopy (FT-IR) or carbon-13 solid-state nuclear magnetic resonance spectroscopy ( 13 C CP / MAS NMR). For example, test the Fourier transform infrared spectroscopy (FT-IR) of the microcapsules with the wall intact or the wall damaged; in the infrared spectrum, there is a peak at 2200-2500 cm -1 , which belongs to the C=O vibration peak of the ureido group (-NH-CO-NH-). Generally, the infrared peak of the C=O vibration peak in the ureido group (-NH-CO-NH-) will have slight differences due to the differences in the structures of the raw material compounds. For example, it is located at 2200-2250 cm -1 , or 2250-2300 cm -1 , 2300-2350 cm -1 , 2350-2400 cm -1 , 2400-2450 cm -1 , or 2450-2500 cm -1 , but generally does not exceed the range of 2200-2500 cm -1 . For another example, test the carbon-13 solid-state nuclear magnetic resonance spectroscopy ( 13 C CP / MAS NMR) of the microcapsules with the wall intact or the wall damaged, and there is a characteristic signal peak at 160±15 ppm, preferably at 160±10 ppm. This characteristic signal peak is the characteristic signal peak of the C in the C=O group of the ureido unit.

[0202] Preferably, the wall of the microcapsule is obtained by reacting raw materials including an isocyanate as an oily wall material and a polyamine as an aqueous wall material. The -NCO in the isocyanate reacts with the -NH 2 in the polyamine to form a -NH-CO-NH- group.

[0203] It is well known in the art that the isocyanate can be selected from: IPDI (isophorone diisocyanate), TDI (toluene diisocyanate), HDI (hexamethylene diisocyanate), H12MDI (4,4'-dicyclohexylmethane diisocyanate), MDI (diphenylmethane diisocyanate), etc., and the polyamine can be selected from diethylamine, triethylenetetramine, ethylenediamine, hexamethylenetetramine, isophorone diamine, etc. The raw materials can be selected according to the requirements of the sustained release, mobility, and stability of the required microcapsules. For example, MDI reacts with ethylenediamine to form the wall of the microcapsule, or MDI reacts with hexamethylenediamine to form the wall of the microcapsule, or MDI reacts with triethylenetetramine to form the wall of the microcapsule.

[0204] Under normal circumstances, in the preparation process of the microcapsules, the amount of substance of -NH 2 in the aqueous wall material should not be lower than the amount of substance of -NCO in the oily wall material. Preferably, the amount of substance of -NH 2 in the aqueous wall material is slightly higher than the amount of substance of -NCO in the oily wall material. For example, compared with the amount of substance of -NCO in the oily wall material, the amount of substance of -NH 2 in the aqueous wall material is 5% - 20% more than the amount of substance of -NCO in the oily wall material, or in some cases, compared with the mass of the oily wall material, the amount of the aqueous wall material is 5% - 20% more than the mass of the oily wall material, so that the oily wall material can fully react.

[0205] In the process of preparing the microcapsules, to ensure the coating rate of the original drug and the thickness and toughness of the wall of the capsule, based on the amount of the original drug, the amount of the oily wall material is generally not lower than 20% of the total mass of the original drug, preferably not lower than 30% of the total mass of the original drug. As the amount of the original drug increases, the amount of the oily wall material should also increase. However, the amount of the oily wall material is not the more the better. Excessive amounts of the oily wall material and the aqueous wall material will also cause the wall of the capsule to be too thick or empty capsules to appear. Under normal circumstances, the amount of the oily wall material is not higher than 60% of the total mass of the original drug, and preferably, it is not higher than 50% of the total mass of the original drug.

[0206] As a preference of any technical solution of the fifth aspect of the present invention, the weight percentage (wt%) of abamectin and fluxapyroxad in the suspending agent is 5 - 25 wt%, and more preferably 5 - 15 wt%.

[0207] As a preference of any technical solution of the fifth aspect of the present invention, the weight ratio of abamectin to fluxapyroxad in the suspending agent is 3:(4 - 12); preferably 3:(5 - 10); most preferably 3:(6 - 9).

[0208] Preferably, for any technical solution of the fifth aspect of the present invention, the weight percentage of the microcapsules in the suspending agent is 10-70 wt%; more preferably, the weight percentage of the microcapsules in the suspending agent is 20-60 wt%; more preferably, the weight percentage of the microcapsules in the suspending agent is 30-50 wt%.

[0209] Among them, the weight percentage of the microcapsules in the suspending agent can be obtained by the following method:

[0210] i. Separating the microcapsules from the suspension by centrifugation:

[0211] The microcapsules are obtained by centrifuging at 10,000 rpm for 5 min, discarding the supernatant, and washing with deionized water;

[0212] ii. Then freeze-drying the obtained microcapsules to obtain microcapsule freeze-dried powder:

[0213] The microcapsule freeze-dried powder is obtained by freeze-drying at -70°C for 8 h;

[0214] iii. Weighing the weight of the microcapsule freeze-dried powder and calculating the percentage content of the microcapsule freeze-dried powder in the suspension.

[0215] For the types and weight percentages of the emulsifying dispersant, defoaming agent, antifreezing agent, preservative, and thickening agent, reference can be made to the description in the fourth aspect of the present invention, which will not be elaborated here.

[0216] [Preparation Method of Abamectin and Fludioxonil Microcapsule Suspending Agent]

[0217] The sixth aspect of the present invention provides a preparation method of the suspending agent according to any technical solution of the fourth or fifth aspect, including:

[0218] Preparing the aqueous phase components, which contain an emulsifying dispersant and a defoaming agent;

[0219] Preparing the oil phase components, which contain abamectin and fludioxonil dissolved in a mixed solvent of dimethyl phthalate, tributyl acetylcitrate, and dioctyl phthalate, as well as an oily wall material;

[0220] Emulsifying, contacting and mixing the prepared oil phase components with the aqueous phase components and shearing and stirring to obtain an oil-in-water emulsion;

[0221] Reacting the capsule wall, mixing the aqueous wall material with the emulsion obtained by emulsification, and carrying out interfacial polymerization to form a capsule wall to obtain microcapsules containing active ingredients, continuously accompanied by stirring operations;

[0222] Insulating and curing to obtain a microcapsule solution;

[0223] Suspension: Add antifreeze and thickening agents to the obtained microcapsule solution, and preferably add preservatives to form a microcapsule suspension containing abamectin and fluxapyroxad.

[0224] [Method for preparing a microcapsule suspension using a microcapsule powder containing abamectin and fluxapyroxad]

[0225] The seventh aspect of the present invention provides a method for preparing a microcapsule suspension, comprising:

[0226] Prepare the microcapsules described in any one of the technical solutions of the first or second aspect of the present invention into microcapsule powders, disperse the microcapsule powders in a liquid medium, add antifreeze and thickening agents, and add or not add preservatives according to actual situations (preservatives are generally added during commercial use) to form a microcapsule suspension containing abamectin and fluxapyroxad.

[0227] Preferably, the weight percentage of microcapsules in the suspension is 10-70 wt%; more preferably, the weight percentage of microcapsules in the suspension is 20-60 wt%; more preferably, the weight percentage of microcapsules in the suspension is 30-50 wt%.

[0228] The present invention also provides the application of the microcapsule suspension containing abamectin and fluxapyroxad described in any one of the fourth or fifth aspects of the present invention, or the microcapsule suspension containing abamectin and fluxapyroxad prepared by the preparation method described in any one of the third aspects in pesticides.

[0229] Preferably, the microcapsule suspension containing abamectin and fluxapyroxad is used to kill nematodes and / or sterilize. Since nematodes are usually located at the roots of plants, after the microcapsule suspension of the present invention is applied to the soil, the microcapsules have good vertical mobility in the soil, are easy to reach the diseased roots of plants and slowly release the active ingredients. Therefore, the microcapsule suspension of the present invention has a good control and killing effect on nematodes at the roots of plants.

[0230] [Definition]

[0231] The term "median particle size D50" used in the present invention, where "median particle size" is also called "median diameter" or "average particle size", and "D50" can also be expressed as "Dv50" or "d(0.5)", represents the particle size corresponding to when the cumulative particle size distribution percentage of a sample reaches 50%. Further, its physical meaning is that 50% of the particles have a particle size greater than it, and 50% of the particles have a particle size less than it.

[0232] The term "maximum particle size D90" used in the present invention, where "D90" can also be expressed as "Dv90" or "d(0.9)", refers to the particle size corresponding to when the cumulative particle size distribution percentage of a sample reaches 90%. Its physical meaning is that 10% of the particles have a particle size larger than it, and 90% of the particles have a particle size smaller than it.

[0233] The "microcapsule suspension" described in the present invention uses a polymer material as the wall material, and by chemical, physical or physicochemical methods, the active ingredient as the core material is encapsulated to form a microcapsule with a semi-permeable capsule membrane, and they are stably dispersed and suspended in an aqueous medium as the continuous phase at a certain concentration.

[0234] The "sustained release" described in the present invention can also be called "controlled release", which refers to the performance that the active ingredient can release the active ingredient at a predetermined speed within a set time and under specific environmental conditions.

[0235] The "persistence" described in the present invention refers to the performance that after application, the drug can be continuously released for a long time to achieve the purpose of prolonging the drug effect.

[0236] 3. Beneficial effects

[0237] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0238] (1) Generally speaking, the present invention uses a mixed solvent of dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate, which is a green and environmentally friendly solvent that can maintain the toughness of the capsule wall and dissolve abamectin and fluxapyroxad at the same time, as a stabilizer to form microcapsules encapsulating the original drugs of abamectin and fluxapyroxad. Combining the particle size characteristics of the microcapsules, the microcapsules have both the persistence of the active ingredient and the mobility of the microcapsules in the soil during application, and have a certain release amount near the depth of the plant roots in the soil, and are expected to become a more effective compound pesticide preparation for preventing and controlling plant root diseases.

[0239] (2) The microcapsules encapsulating the original drugs of abamectin and fluxapyroxad of the present invention have good persistence. Examples 1-7 show that abamectin and fluxapyroxad can maintain a relatively uniform release within 300 h. Compared with the prior art of the abamectin·fluxapyroxad microcapsule suspension-suspension agent that only encapsulates abamectin, fluxapyroxad in the present invention also achieves long-term slow release.

[0240] (3) The microcapsules encapsulating the original drugs of abamectin and fluxapyroxad of the present invention have a moderate toughness of the capsule wall and an appropriate particle size. The capsule wall is not easily broken, and has good mobility in the soil. A certain proportion of the microcapsules can move to a certain depth (9-12 cm) in the soil and then release, ensuring that the microcapsules can have a certain concentration near the depth of the plant roots in the soil, and can be effectively used for killing diseases such as nematodes on the plant roots.

[0241] (4) The microcapsule suspension containing abamectin and fluxapyroxad of the present invention has uniformly dispersed microcapsules that do not agglomerate and are not easily broken, with good cold and heat storage stability. In the soil application environment, both original drugs are encapsulated in the microcapsules. The microcapsules have good mobility in the soil, high utilization rate of the original drugs, long residual period, and can play a therapeutic role in the plant root lesions deep in the soil body. Description of the Drawings

[0242] Figure 1 Schematic diagram for the preparation of the microcapsule suspension of abamectin and fluxapyroxad in the examples;

[0243] Figure 2 SEM image of the microcapsules in the microcapsule suspension of abamectin and fluxapyroxad in Example 1;

[0244] Figure 3 SEM image of the microcapsules in the microcapsule suspension of abamectin and fluxapyroxad in Example 2;

[0245] Figure 4 SEM image of the microcapsules in the microcapsule suspension of abamectin and fluxapyroxad in Example 3;

[0246] Figure 5 SEM image of the microcapsules in the microcapsule suspension of abamectin and fluxapyroxad in Comparative Example 1;

[0247] Figure 6 SEM image of the microcapsules in the microcapsule suspension of abamectin and fluxapyroxad in Comparative Example 2;

[0248] Figure 7 Cumulative release diagram of abamectin in the microcapsules of abamectin and fluxapyroxad in Example 8;

[0249] Figure 8 Cumulative release diagram of fluxapyroxad in the microcapsules of abamectin and fluxapyroxad in Example 8;

[0250] Figure 9 Cumulative release diagram of abamectin and fluxapyroxad in the microcapsules of abamectin and fluxapyroxad prepared in Example 1;

[0251] Figure 10 Infrared spectrum diagram in Example 11, where: a: abamectin + fluxapyroxad original drug; b: abamectin + fluxapyroxad microcapsules; c: blank microcapsules. Detailed Embodiments

[0252] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0253] For those not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0254] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement, or value. One of ordinary skill in the art can readily determine the degree of flexibility for a particular variable.

[0255] Concentrations, amounts, and other numerical data may be presented herein in a range format. It should be understood that such range formats are used merely for convenience and brevity and should be interpreted flexibly as including not only the explicitly recited values as the limits of the range, but also all individual values or sub-ranges subsumed within the stated range as if each value and sub-range were explicitly recited. For example, a numerical range of about 1 to about 4.5 should be interpreted as including not only the explicitly recited limits of 1 to about 4.5, but also the individual numbers (such as 2, 3, 4) and sub-ranges (such as 1 to 3, 2 to 4, etc.). The same principle applies to ranges that recite only one numerical value, such as "less than about 4.5", which should be interpreted as including all of the above values and ranges. In addition, this interpretation should apply regardless of the breadth of the range or feature described.

[0256] Determination method of coating rate in the examples: Weigh 1 g of the microcapsule suspension sample, mix it evenly with 5 mL of 20% ethylene glycol aqueous solution, place it in a 10 mL centrifuge tube, centrifuge it at 5000 rmp in a high-speed centrifuge for 6 min, take out the supernatant, filter it, and then determine it using a high-performance liquid chromatograph. The HPLC detection methods for abamectin and fluxapyroxad are as follows:

[0257] HPLC detection conditions for abamectin:

[0258] Mobile phase: methanol: water = 90:10 (v:v); detection wavelength: 250 nm; flow rate: 1.0 mL / min; column temperature: 30 °C.

[0259] HPLC detection conditions for fluxapyroxad:

[0260] Mobile phase: acetonitrile: water = 60:40 (v:v); detection wavelength: 220 nm; flow rate: 1.0 mL / min; column temperature: 30 °C.

[0261] Abamectin coating rate = (1 - concentration detected by liquid chromatography / original abamectin concentration) × 100%

[0262] Fludioxonil coating rate = (1 - concentration detected by liquid chromatography / original fludioxonil concentration) × 100%

[0263] The original abamectin concentration refers to the weight percentage of the initially added technical abamectin based on the total amount of the microcapsule suspension being 100%; the original fludioxonil concentration refers to the weight percentage of the initially added technical fludioxonil based on the total amount of the microcapsule suspension being 100%.

[0264] Reagents:

[0265]

[0266] Instruments:

[0267]

[0268] The present invention will be further described below in conjunction with specific embodiments.

[0269] Example 1

[0270] In this example, the components and parts by weight of the abamectin and fludioxonil microcapsule liquid are as follows:

[0271]

[0272] The preparation method of the above abamectin and fludioxonil microcapsule liquid is as follows:

[0273] (1) Preparation of the aqueous phase components: Add an emulsifying dispersant and an antifoaming agent to water, mix evenly, and set aside.

[0274] (2) Preparation of the oil phase components: Dissolve abamectin and fludioxonil in dimethyl phthalate, tributyl acetylcitrate, and dioctyl phthalate, add an oily wall material, stir evenly, and set aside.

[0275] (3) At a water bath temperature of 60 °C, under high-speed shear stirring at 12000 - 15000 rmp, add (2) to (1), shear to an appropriate particle size to form a stable oil-in-water (O / W) emulsion.

[0276] (4) While stirring, at a water bath temperature of 60 °C, add an aqueous wall material dropwise to the emulsion in (3).

[0277] (5) Heat and keep warm to form capsules, with the heating temperature being 65 °C and the holding time being 3.5 hours to form the abamectin and fludioxonil microcapsule liquid.

[0278] The SEM of the microcapsules is as Figure 2As shown, the microcapsules have a good external morphology, presenting a spherical shape, without any damage, with relatively uniform particle sizes, and the surface of the microcapsules is relatively smooth and dense.

[0279] (6) The microcapsules in the microcapsule liquid can be obtained by taking a part of the microcapsule liquid through the following method:

[0280] i. Separate the microcapsules from the microcapsule liquid by centrifugation:

[0281] Centrifuge at 10000 rpm for 5 min, discard the supernatant, and wash with deionized water to obtain the microcapsules;

[0282] ii. Then freeze-dry the obtained microcapsules to obtain microcapsule freeze-dried powder:

[0283] Freeze-dry at -70 °C for 8 h to obtain the microcapsule freeze-dried powder;

[0284] iii. Weigh the mass of the microcapsule freeze-dried powder.

[0285] (7) Add an antifreeze, a preservative, and a thickener to the abamectin and fluxapyroxad microcapsules formed in (5), and stir evenly to form an abamectin and fluxapyroxad microcapsule suspension.

[0286] For the abamectin and fluxapyroxad microcapsule suspension prepared by the above preparation method, the components and contents are as follows (calculated based on the total weight of the suspension being 100%, where the oily wall material and the aqueous wall material are the dosages, and this meaning is understood in the examples):

[0287]

[0288] Example 2

[0289] In this example, the components and parts by weight of the abamectin and fluxapyroxad microcapsule liquid are as follows:

[0290]

[0291]

[0292] The preparation method steps (1)-(6) of the above abamectin and fluxapyroxad microcapsule liquid are the same as those in Example 1;

[0293] (7) Add an antifreeze, a preservative, and a thickener to the abamectin and fluxapyroxad microcapsules formed in (5), and stir evenly to form an abamectin and fluxapyroxad microcapsule suspension.

[0294] For the abamectin and fluxapyroxad microcapsule suspension prepared by the above preparation method, the components and contents are as follows (calculated based on the total weight of the suspension being 100%):

[0295]

[0296] Example 3

[0297] In this example, the components and parts by weight of the abamectin and fluxapyroxad microcapsule liquid are as follows:

[0298]

[0299] The preparation method steps (1)-(6) of the above abamectin and fluxapyroxad microcapsule liquid are the same as those in Example 1;

[0300] (7) In the abamectin and fluxapyroxad microcapsules formed in (5), add antifreeze, preservative, and thickener, and stir evenly to form an abamectin and fluxapyroxad microcapsule suspension.

[0301] The components and contents of the abamectin and fluxapyroxad microcapsule suspension prepared by the above preparation method are as follows (based on the total weight of the suspension being 100%):

[0302]

[0303]

[0304] Example 4

[0305] In this example, the components and parts by weight of the abamectin and fluxapyroxad microcapsule liquid are as follows:

[0306]

[0307] The preparation method steps (1)-(6) of the above abamectin and fluxapyroxad microcapsule liquid are the same as those in Example 1;

[0308] (7) In the abamectin and fluxapyroxad microcapsules formed in (5), add antifreeze, preservative, and thickener, and stir evenly to form an abamectin and fluxapyroxad microcapsule suspension.

[0309] The components and contents of the abamectin and fluxapyroxad microcapsule suspension prepared by the above preparation method are as follows (based on the total weight of the suspension being 100%):

[0310]

[0311] Example 5

[0312] In this example, the components and parts by weight of the abamectin and fluxapyroxad microcapsule liquid are as follows:

[0313]

[0314] The preparation method steps (1)-(6) of the above abamectin and fluxapyroxad microcapsule liquid are the same as those in Example 1;

[0315] (7) In the avermectin and fluxapyroxad microcapsules formed in (5), add an antifreeze agent, a preservative, and a thickening agent, and stir evenly to form an avermectin and fluxapyroxad microcapsule suspension.

[0316] For the avermectin and fluxapyroxad microcapsule suspension prepared by the above preparation method, the components and contents are as follows (based on the total weight of the suspension being 100%):

[0317]

[0318] Example 6

[0319] In this example, the components and parts by weight of the avermectin and fluxapyroxad microcapsule liquid are as follows:

[0320]

[0321] The preparation method steps (1)-(6) of the above avermectin and fluxapyroxad microcapsule liquid are the same as those in Example 1;

[0322] (7) In the avermectin and fluxapyroxad microcapsules formed in (5), add an antifreeze agent, a preservative, and a thickening agent, and stir evenly to form an avermectin and fluxapyroxad microcapsule suspension.

[0323] For the avermectin and fluxapyroxad microcapsule suspension prepared by the above preparation method, the components and contents are as follows (based on the total weight of the suspension being 100%):

[0324]

[0325] Example 7

[0326] In this example, the components and parts by weight of the avermectin and fluxapyroxad microcapsule liquid are as follows:

[0327]

[0328]

[0329] The preparation method steps (1)-(6) of the above avermectin and fluxapyroxad microcapsule liquid are the same as those in Example 1;

[0330] (7) In the avermectin and fluxapyroxad microcapsules formed in (5), add an antifreeze agent, a preservative, and a thickening agent, and stir evenly to form an avermectin and fluxapyroxad microcapsule suspension.

[0331] For the avermectin and fluxapyroxad microcapsule suspension prepared by the above preparation method, the components and contents are as follows (based on the total weight of the suspension being 100%):

[0332]

[0333] The property parameters of the microcapsules and the microcapsule suspension prepared in Examples 1-7 are shown in Table 1.

[0334] Table 1 Property parameters of the microcapsules and the microcapsule suspension prepared in Examples 1-7

[0335]

[0336] Note: The unit of the abamectin content in the microcapsules, g / g, represents the weight grams of abamectin contained in each gram of the microcapsules. The unit of the fluxapyroxad content in the microcapsules, g / g, represents the weight grams of fluxapyroxad contained in each gram of the microcapsules.

[0337] Comparative Example 1

[0338] Effect of the choice of stabilizer on the microcapsules

[0339] Other conditions are the same as in Example 1, except that: dioctyl phthalate is replaced with solvent oil 150#, and in order to completely dissolve abamectin and fluxapyroxad, the amount of solvent oil is increased by 20% (calculated based on the total weight of the microcapsule suspension being 100%), to obtain microcapsules containing abamectin and fluxapyroxad and the microcapsule suspension. Take the microcapsule suspension for SEM as Figure 5 shown, and more original drugs are precipitated outside the microcapsule particles.

[0340] As shown in Table 2, using solvent oil 150# as the solvent instead of dioctyl phthalate, on the one hand, it is necessary to increase the amount of solvent oil to dissolve the original drugs, and on the other hand, the coating rates of abamectin and fluxapyroxad in the obtained microcapsule suspension are relatively low, and the thermal storage stability and cold storage stability of the microcapsule suspension sample in Example 10 are unqualified (Table 7).

[0341] Comparative Example 2

[0342] Effect of the choice of stabilizer on the microcapsules

[0343] Other conditions are the same as in Example 1, except that: dioctyl phthalate is replaced with N-methylpyrrolidone, and the dosage remains unchanged, to obtain microcapsules containing abamectin and fluxapyroxad and the microcapsule suspension. Take the microcapsule suspension for SEM as Figure 6 shown, and there are more depressions in the capsule wall of the microcapsule particles.

[0344] As shown in Table 2, when N-methylpyrrolidone is used instead of dioctyl phthalate as the solvent, although it has good solubility for the technical material, since N-methylpyrrolidone has a certain solubility for the capsule wall, it is not conducive to maintaining the toughness of the capsule wall. The prepared microcapsule capsule wall collapses severely, and it also results in low contents of abamectin and fluxapyroxad in the microcapsule suspension. Moreover, the thermal storage stability and cold storage stability of the microcapsule suspension in Example 10 are unqualified (Table 7).

[0345] Comparative Example 3

[0346] Effect of stabilizer selection on microcapsules

[0347] Other conditions are the same as in Example 1, except that: dioctyl phthalate is not added, and the technical material cannot be dissolved, resulting in the inability to further prepare microcapsules and microcapsule suspensions.

[0348] Comparative Example 4

[0349] Effect of microcapsule average particle size on microcapsule properties

[0350] Other conditions are the same as in Example 1, except that: step (3) in the preparation method of the abamectin and fluxapyroxad microcapsule liquid is as follows:

[0351] (3) Under high-speed shearing and stirring at 6000 - 8000 rmp, add (2) to (1) to form a stable oil-in-water (O / W) emulsion.

[0352] Other steps are the same, and microcapsules and microcapsule suspensions containing abamectin and fluxapyroxad are obtained.

[0353] As shown in Table 2, the microcapsules obtained at a shearing speed of 6000 - 8000 rmp have a larger particle size, are prone to sedimentation during storage, and water separates out on the upper layer; moreover, when the microcapsule particle size is large, the release of the technical material is too fast to achieve the purpose of long-acting release (Tables 3 and 4). And when the microcapsule size is relatively large, the thermal storage stability and cold storage stability of the microcapsule suspension in Example 10 are unqualified (Table 7).

[0354] Comparative Example 5

[0355] Effect of microcapsule average particle size on microcapsule properties

[0356] Other conditions are the same as in Example 1, except that: step (3) in the preparation method of the abamectin and fluxapyroxad microcapsule liquid is as follows:

[0357] (3) Under high-speed shearing and stirring at 20000 - 22000 rmp, add (2) to (1) to form a stable oil-in-water (O / W) emulsion.

[0358] The other steps are the same, and microcapsules containing abamectin and fluxapyroxad and a microcapsule suspension are obtained.

[0359] As shown in Table 2, the microcapsules obtained at a shear rate of 22000 - 25000 rmp have a smaller particle size, and water is prone to separate out at the lower layer during storage; moreover, when the particle size of the microcapsules is small, the release of the original drug is too slow to achieve the purpose of exerting the drug effect (Tables 3 and 4). And when the size of the microcapsules is relatively small, the thermal storage stability and cold storage stability of the microcapsule suspension in Example 10 are unqualified (Table 7).

[0360] Table 2 Property parameters of the microcapsules and microcapsule suspensions prepared in Comparative Examples 1, 2, 4, and 5

[0361]

[0362] Example 8

[0363] Original drug release experiments of the microcapsule suspensions prepared in Examples 1 - 7 and Comparative Examples 1 - 5 (except Comparative Example 3)

[0364] The release behavior of the microcapsules in the soil was simulated by using microcapsule release kinetics research.

[0365] The dialysis bag method was used to study the microcapsule release kinetics. The purchased dialysis bag (cut-off molecular weight: 8000 - 14000) was cut into small sections about 5 cm long for pretreatment. Accurately weigh 1.00 g of the newly prepared microcapsule suspension and place it in the dialysis bag. The dialysis bag was immersed in a 100 mL conical flask containing 50 mL of the release medium. The release medium was 50 / 50 acetonitrile / water (v / v). The release test was carried out in a double-layer shaking incubator at 25 ± 2 °C with a rotation speed of 100 rpm. At different time intervals, an equal amount (1 mL) of the medium outside the dialysis bag was collected, and 1 mL of the acetonitrile / water solution of the release medium was added to keep the volume of the release medium always 50 mL. The sampling solution passed through an organic phase microporous filter membrane with a pore size of 0.22 μm. The contents of abamectin and fluxapyroxad in the filtrate were determined by high performance liquid chromatography. According to the determination results, the cumulative release amounts of the two original drugs in the microcapsules were calculated respectively.

[0366] Formula for calculating the cumulative release amount:

[0367]

[0368] Among them, Ct represents the concentration of abamectin (fluxapyroxad) in the release medium at time t, mt-act represents the cumulative release amount of abamectin (fluxapyroxad) at time t, v represents the volume of the release medium taken out each time (1 mL in this experiment), and V represents the total volume of the release medium (50 mL in this experiment).

[0369] The cumulative release amount of abamectin over time is as shown in Table 3 below:

[0370] Table 3 Cumulative release amount of avermectin over time

[0371]

[0372]

[0373] The cumulative release curve of avermectin over time is as Figure 7 shown. The microcapsule suspension agents prepared in Examples 1-7 showed a relatively uniform release state within 312 h. Among them, the release rate from 0 to 192 h was slightly higher than that from 192 to 312 h. There was a phenomenon of burst release during the release of avermectin from the microcapsules prepared in Comparative Example 1 (96-120 h), and the cumulative release amount reached about 70% to 80%. The reason for this phenomenon may be that the solubility of the solvent (stabilizer) for dissolving the original drug was poor, resulting in the easy rupture of the capsule wall and the sudden release of the original drug. There was a phenomenon of burst release during the release of avermectin from the microcapsules prepared in Comparative Example 2 (48-168 h). The reason for this phenomenon may be that the solvent (stabilizer) for dissolving the original drug corroded the capsule wall, resulting in a thinner capsule wall and easy rupture to release the original drug. The microcapsules prepared in Comparative Example 4 had a larger particle size and a thinner capsule wall, and there was a phenomenon of burst release during the oscillatory release process (48-168 h). The microcapsules prepared in Comparative Example 5 had a smaller particle size and it was difficult to release the active ingredient.

[0374] The cumulative release amount of fluxapyroxad over time is as shown in Table 4 below:

[0375] Table 4 Cumulative release amount of fluxapyroxad over time

[0376]

[0377] As Figure 8 shown, the cumulative release curve of fluxapyroxad was relatively similar to that of avermectin. The microcapsule suspension agents prepared in Examples 1-7 showed a relatively uniform release state within 312 h. Among them, the release rate from 0 to 192 h was slightly higher than that from 192 to 312 h. There was a phenomenon of burst release during the release of fluxapyroxad from the microcapsules prepared in Comparative Example 1 (96-120 h). The reason for this phenomenon may be that the solubility of the solvent (stabilizer) for dissolving the original drug was poor, resulting in the easy rupture of the capsule wall and the sudden release of the original drug. There was a phenomenon of burst release during the release of fluxapyroxad from the microcapsules prepared in Comparative Example 2 (48-144 h). The reason for this phenomenon may be that the solvent (stabilizer) for dissolving the original drug corroded the capsule wall, resulting in a thinner capsule wall and easy rupture to release the original drug; the microcapsules prepared in Comparative Example 4 had a larger particle size and a relatively thinner capsule wall, and there was a phenomenon of burst release during the oscillatory release process (48-144 h). The microcapsules prepared in Comparative Example 5 had a smaller particle size and it was difficult to release the active ingredient.

[0378] Combined with the cumulative release curves of abamectin and fluxapyroxad, as Figure 9 shown, in Example 1, the cumulative release percentages of abamectin and fluxapyroxad were basically the same within 312 h, that is, they were released uniformly and long-acting basically according to the feeding percentage during coating.

[0379] Example 9

[0380] The mobility experiment of the microcapsule suspension prepared in Examples 1-7 and Comparative Examples 1-5 (except Comparative Example 3) in soil

[0381] To investigate the leaching characteristics of abamectin and fluxapyroxad in soil, a leaching experiment was carried out on the prepared microcapsule suspension by the soil column leaching method. Through the soil column leaching test, the leaching characteristics of the microcapsule suspension prepared in Examples 1-7 and Comparative Examples 1-5 (except Comparative Example 3) in soil were determined. Weigh 720 g of the tested soil passed through a 20-mesh sieve and fill it into the cylindrical PVC plastic pipe to make a soil column with a height of 30 cm. Spread 1 cm thick quartz sand on the surface of the soil column, and add 0.1 mol / L CaCl 2 solution to reach 60% of the saturated water holding capacity. Then, uniformly drip the microcapsule suspension prepared in Examples 1-7 and Comparative Examples 1-5 (except Comparative Example 3) at 10 mg / cm 2 a.i. into the quartz sand layer, and leach it with 0.01 mol / L CaCl 2 solution at a rate of 30 mL / h, and collect a total of 300 mL of the leaching solution. Each treatment was repeated three times and the average value was taken. After the leaching was completed, the soil column was evenly divided into 10 sections, and the contents of abamectin and fluxapyroxad in each section of the soil and the leachate were measured respectively. The content calculation method is as follows:

[0382]

[0383] In the formula: R i : the proportion of the pesticide content in each section of the soil and the leachate (%); m i : the mass of the pesticide in each section of the soil and the leachate (mg); m o : the total amount of pesticide added (mg).

[0384] The content of abamectin varying with depth is as follows:

[0385] Table 5 Content of abamectin varying with depth

[0386]

[0387] The content of fluxapyroxad varying with depth is as follows:

[0388] Table 6 Content of fluxapyroxad varying with depth

[0389]

[0390] Since the root lesion sites are generally about 10 cm below the soil surface, it is desired that the microcapsules containing the technical material can have a certain release at an appropriate depth below the soil surface. In this experiment, the vertical mobility of the microcapsules in the soil mass was simulated. The results showed that the percentage content of abamectin in the microcapsules prepared in Examples 1-7 reached 4% - 8% near the depth of 9 - 12 cm. Similar to the mobility of abamectin in the soil mass, fluxapyroxad in all 7 examples could reach the depth of 9 - 12 cm, reaching the disease site, and the percentage content reached 3% - 7%. It indicated that the microcapsule samples prepared in Examples 1-7 had good vertical mobility in the soil column. In contrast, after the microcapsules prepared in Comparative Examples 1, 2 and 4 were applied, abamectin and fluxapyroxad basically concentrated at 0 - 6 cm below the soil surface and could not move vertically, almost distributed in the upper part of the soil, with poor vertical distribution and mobility in the soil. It should be noted that a relatively high content of abamectin and fluxapyroxad was detected in the leachate of Comparative Example 5, which might be due to the fact that the average particle size of the microcapsules was too small, resulting in too good mobility in the soil.

[0391] Example 10

[0392] Storage stability experiment of the microcapsule suspension prepared in Examples 1-7 and Comparative Examples 1-5

[0393] The hot storage stability was determined according to the method in the National Standard of the People's Republic of China "Determination Method for Hot Storage Stability of Pesticides", GB / T 19136-2003. Specifically: Use a syringe to inject about 30 mL of the test sample into a clean ampoule bottle (avoiding the test sample contacting the bottleneck), place this ampoule bottle in an ice-salt bath for refrigeration, seal it with a high-temperature flame (avoiding solvent volatilization), and cool to room temperature and weigh. Place the sealed ampoule bottle in a metal container, and then place the metal container in a constant temperature oven (or constant temperature water bath) at (54 ± 2) °C for 14 d. Take it out, wipe the outside of the ampoule bottle clean and weigh. For the test sample with unchanged mass, complete the inspection of the specified items such as the content of the active ingredient within 24 h.

[0394] The inspection indexes are as follows:

[0395] (1) Macroscopic observation: It is qualified if it can flow after 14 d, without pasting, and the water separation is less than 20%;

[0396] (2) Microscopic observation: It is qualified if the microcapsules are not agglomerated and have a good shape;

[0397] (3) Content analysis: It is qualified if the effective content of the technical material is within the range of ±3%;

[0398] (4) Suspension rate analysis: It is qualified if the suspension rate is greater than or equal to 95%;

[0399] The cold storage stability was determined according to the method in the national standard of the People's Republic of China, "Determination Method for Low Temperature Stability of Pesticides", GB / T 19137-2003. Specifically: Take 80 mL of the test sample and place it in a 100 mL beaker. Cool it to (0 ± 2) °C in a refrigerator, keep it for 1 h, stir it once every 15 min for 15 s each time, and observe whether there is any change in appearance. Put the beaker back into the refrigerator and continue to place it at (0 ± 2) °C for 7 d. After 7 d, take out the beaker, restore it to room temperature, and test the sieve analysis, suspension rate or other necessary physical and chemical indexes.

[0400] The inspection indexes are as follows:

[0401] (1) Macroscopic observation: After 7 d, it can flow, no crystallization occurs, and the water separation is less than 15% is qualified;

[0402] (2) Microscopic observation: The microcapsules are not agglomerated and have a good shape is qualified;

[0403] (3) Content analysis: The effective content of the technical material within the range of ±3% is qualified;

[0404] (4) Suspension rate analysis: The suspension rate is greater than or equal to 95% is qualified;

[0405] Table 7 Thermal storage stability and cold storage stability of the microcapsule suspension in Examples 1-7 and Comparative Examples 1, 2, 4 and 5

[0406]

[0407] Example 11

[0408] Fourier transform infrared spectroscopy detection

[0409] Method: After pressing the sample with potassium bromide, the structure of the sample to be tested was identified by infrared spectroscopy. Weigh 2 mg of the dry sample to be tested, add KBr, grind it into powder, then press it into tablets, and scan at a wavelength of 4000-450 cm in the Fourier transform infrared spectrum -1 to obtain the infrared spectrum.

[0410] Figure 10 Curves a-c respectively represent the infrared spectra of abamectin + fluxapyroxad technical material (the same ratio as in Example 1), abamectin + fluxapyroxad microcapsules (prepared in Example 1), and blank microcapsules without technical material and stabilizer (basically the same as the wall material, ratio and preparation method in Example 1).

[0411] In the infrared curve a, the broad peak around 3000-2850 cm -1 is the stretching vibration absorption peak of methyl and methylene groups of abamectin; 1720 cm -1The strong absorption peak at [location] is the stretching vibration absorption peak of the carbonyl group in fluxapyroxad. In the infrared c curve, the broad peak at 2250 cm -1 is the stretching vibration absorption peak of the carbonyl group in the polyurea. Compared with the infrared c curve, there is an obvious infrared absorption peak at around 2250 cm -1 in the infrared b curve, indicating that the isocyanate group reacts with the amino group to form polyurea. At the same time, the characteristic absorption peak at around 3000 - 2850 cm -1 and the strong absorption peak at 1720 cm -1 are the characteristic absorption peaks of the technical material. The infrared b curve contains both the polyurea absorption peak and the characteristic absorption peak of the technical material, further corroborating that abamectin and fluxapyroxad technical materials are successfully encapsulated by the capsule wall formed by the reaction of MDI and ethylenediamine.

[0412] The above content gives a schematic description of the present invention and its implementation manners. This description is not restrictive. What is shown in the embodiments is only one of the implementation manners of the present invention, and the actual implementation manners are not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention, design similar implementation manners and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A microcapsule suspension containing abamectin and fluxapyroxad, characterized in that, it comprises microcapsules dispersed in an aqueous liquid medium, and the microcapsules contain the technical material and a stabilizer; the technical material contains a first active ingredient and a second active ingredient; the first active ingredient contains abamectin, and the second active ingredient contains fluxapyroxad; the stabilizer contains dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate; the median particle size D50 of the microcapsules is 0.6 - 5.0 μm, and the maximum particle size D90 is 1.0 - 15.0 μm; wherein, the abamectin in the suspension accounts for 1 - 20 wt% of the weight of the suspension; the fluxapyroxad in the suspension accounts for 1 - 20 wt% of the weight of the suspension.

2. The microcapsule suspension containing abamectin and fluxapyroxad according to claim 1, characterized in that, the percentage of the sum of the weights of abamectin and fluxapyroxad in the suspension is 5 - 25 wt%, and further preferably 5 - 15 wt%.

3. The microcapsule suspension containing abamectin and fluxapyroxad according to claim 1, characterized in that, the weight ratio of abamectin to fluxapyroxad in the suspension is 3:(4 - 12); preferably 3:(5 - 10); most preferably 3:(6 - 9).

4. The microcapsule suspension containing abamectin and fluxapyroxad according to claim 1, characterized in that, the sum of the weights of the stabilizer in the suspension accounts for 20% - 40%, preferably 20 - 30%.

5. The microcapsule suspension containing abamectin and fluxapyroxad according to claim 1, characterized in that, the content of dioctyl phthalate accounts for 3% - 20% of the suspension.

6. The microcapsule suspension containing abamectin and fluxapyroxad according to claim 1, characterized in that, the content of dimethyl phthalate accounts for 10% - 20% of the suspension; preferably 15% - 20%.

7. The microcapsule suspension containing abamectin and fluxapyroxad according to claim 1, characterized in that, the content of tributyl acetylcitrate accounts for 3% - 10% of the suspension; preferably 3% - 8%.

8. A microcapsule suspension containing abamectin and fluxapyroxad, characterized in that, it comprises microcapsules dispersed in an aqueous liquid medium, and the microcapsules contain abamectin, fluxapyroxad, dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate; the median particle size D50 of the microcapsules is 0.6 - 5.0 μm, and the maximum particle size D90 is 1.0 - 15.0 μm; preferably, the median particle size D50 of the microcapsules is 0.8 - 4.0 μm, and the maximum particle size D90 is 1.2 - 12.0 μm; preferably, the median particle size D50 of the microcapsules is 1.0 - 3.0 μm, and the maximum particle size D90 is 2.0 - 6.0 μm; preferably, the median particle size D50 of the microcapsules is 1.0 - 2.0 μm, and the maximum particle size D90 is 2.5 - 5.0 μm; calculated by weight percentage (wt%), the suspension contains:

9. The microcapsule suspension containing abamectin and fluxapyroxad according to claim 8, characterized in that, it further contains: antifreeze 0.1 - 10 wt% thickener 1 - 20 wt%.

10. The microcapsule suspension containing abamectin and fluxapyroxad according to claim 9, characterized in that, it further contains: preservative 0.1 - 5 wt%.

11. The microcapsule suspension containing abamectin and fluxapyroxad according to claim 10, characterized in that, by weight percentage (wt%), the suspension contains:

12. The microcapsule suspension containing abamectin and fluxapyroxad according to any one of claims 1 - 11, characterized in that, the emulsifying dispersant is selected from one or more of sodium lignosulfonate or calcium salt, alkylaryl polyoxyethylene polyoxypropylene ether, sodium naphthol sulfonate formaldehyde condensate, alkylphenol polyoxyethylene polyoxypropylene ether, styrene maleic anhydride, methylnaphthalene sulfonic acid formaldehyde condensate, castor oil ethylene oxide adduct, alkylphenol polyoxyethylene polyoxypropylene ether, alkyl - diethylene glycol ether - sulfonate, N - methyl - oleoyl - taurine sodium salt; the defoamer is selected from one or more of SAG1522, silicone, silicone oil, fatty alcohols with 8 - 10 carbon atoms, phosphate esters, saturated fatty acids with 10 - 20 carbon atoms and amides; the antifreeze is selected from, but not limited to, one or more of ethanol, isopropanol, ethylene glycol, propylene glycol, glycerol, diethylene glycol, ethylene glycol butyl ether, propylene glycol butyl ether, ethylene glycol butyl ether acetate, urea; the thickener is selected from one or more of clay, rock powder, chalk, quartz, clay, montmorillonite, sodium sulfate, silica, diatomaceous earth, pumice, gypsum, talc, bentonite, kaolin, attapulgite, light calcium carbonate, clay, montmorillonite, magnesium aluminum silicate, activated clay, white carbon black, ammonium sulfate, benzofuran resin, superphosphate, alumina, calcite, marble, pumice, xanthan gum, arabic gum, gelatin or cyclodextrin; the preservative is selected from one or more of sodium benzoate, benzoic acid, carbopol, potassium sorbate, sorbic acid or sulfite.

13. The preparation method of the suspension according to any one of claims 1 - 12, comprising: preparing the aqueous phase component, which contains an emulsifying dispersant and a defoamer; preparing the oil phase component, which contains abamectin and fluxapyroxad dissolved in a mixed solvent of dimethyl phthalate, tributyl acetylcitrate and dioctyl phthalate, and an oily wall material; emulsifying, making the prepared oil phase component contact and mix with the aqueous phase component and shear and stir to obtain an oil - in - water emulsion; capsule wall reaction, making the aqueous wall material mix with the emulsified emulsion, and carrying out interfacial polymerization to form a capsule wall to obtain microcapsules containing active ingredients, continuously accompanied by stirring operation; heat preservation and curing to obtain a microcapsule solution; suspending, adding an antifreeze and a thickener to the obtained microcapsule solution to form a microcapsule suspension containing abamectin and fluxapyroxad.

14. The application of the microcapsule suspension containing abamectin and fluxapyroxad according to any one of claims 1 - 12 in pesticides.

15. The application according to claim 14, for killing nematodes and / or sterilizing bacteria.

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