Spinetoram microemulsion as well as preparation method and application thereof

Abstract

The invention provides a spinetoram microemulsion as well as a preparation method and application thereof. The microemulsion belongs to a thermodynamic stable system, the effective components stably exist in the form of nanoscale particles, the microemulsion is stable and not layered after being stored for a long time, the pesticide effect exertion is not affected, and when the microemulsion is used in a spraying mode, the leaf surface wetting performance is excellent, and the leaf surface spreading capacity is high. The microemulsion disclosed by the invention can give full play to the pesticide effect, obviously improve the prevention and treatment effect of chemical agents, ensure the safety of crops, and effectively prevent and treat thrips, chilo suppressalis, red spiders, aphids and other resistant bugs.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticide preparations, in particular to a spinetoram microemulsion and a preparation method and application thereof. Background Art

[0002] Pesticide formulations are diverse, primarily including wettable powders, emulsifiable concentrates, granules, suspension concentrates, and microemulsions. With increasingly stringent environmental regulations, the shift toward water-based pesticide formulations is accelerating. Water-based formulations (such as microemulsions and emulsions in water) replace organic solvents with water, reducing volatile organic compound (VOC) emissions, environmental pollution, and flammability risks.

[0003] Pesticide microemulsions (MEs) are thermodynamically stable dispersions with water as the continuous phase. They consist of a liquid pesticide technical (or a solid technical dissolved in an organic solvent), a surfactant, a co-surfactant, and water, forming a transparent or translucent homogeneous liquid with a particle size of 0.01-0.1 μm. Pesticide microemulsions are environmentally safe, offer efficient penetration, are highly stable, and have low toxicity and residue, making them a popular alternative to emulsifiable concentrates.

[0004] Spinetoram is a new biogenic insecticide developed by Dow AgroSciences (now Corteva) in the United States, based on spinosad through chemical modification. It belongs to the second generation of spinosad insecticides. Spinetoram has low solubility in water but is readily soluble in organic solvents such as methanol and acetone. It degrades rapidly under light and has a short half-life in soil, resulting in minimal environmental impact. Spinetoram has contact and stomach poisoning properties, acting on the nicotinic acetylcholine receptors (nAChR) and gamma-aminobutyric acid receptors (GABA) in the insect nervous system, interfering with signal transmission and causing paralysis and death. Its activity is 10 times that of spinosad and is effective against pests in the orders Lepidoptera, Thysanoptera, and Diptera, including the rice stem borer, rice leaf roller, rice thrips, diamondback moth, beet armyworm, Spodoptera litura, bean pod borer, leafminer, and aphids. It has low toxicity to mammals, birds, and fish, is safe for bees, and is easily degraded in the environment. It can be used on field crops, vegetables, and fruits, such as rice, cabbage, corn, eggplant, grapes, and mangoes. Common formulations of spinetoram include suspension concentrates and water-dispersible granules.

[0005] The 60g / L spinetoram suspension concentrate widely used in the market is a thermodynamically unstable system. Long-term storage can easily lead to crusting and stratification, which affect its use. There are also differences between batches of products, resulting in unstable efficacy.

[0006] The prior art discloses a variety of pesticide formulations containing spinetoram, such as CN101874486A, CN102246799A, CN102396487A, etc. However, these patent applications all focus on the synergistic effect of combining spinetoram with other pesticide active ingredients. Moreover, although some patent applications disclose their microemulsion formulations and related formulas, none of them conduct quality index testing and toxicological experiments, and it is unclear whether they can actually prepare qualified spinetoram microemulsion products. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a spinetoram microemulsion, which comprises the following components, calculated by mass percentage: 1-20% spinetoram, 10-25% emulsifier, 5-15% synergist, 5-15% antifreeze, 20-50% solvent, and deionized water to make up 100%.

[0008] Among them, the emulsifier is castor oil polyoxyethylene ether and polyether phosphate; the synergist is one or more of plant-based polyols, piperonyl ether, piperonyl phosphate, methyl piperonyl phosphate, octachlorodipropyl ether, etc.; the antifreeze is ethanol; and the solvent is dimethyl carbonate, S-200# solvent oil, and ethanol.

[0009] Preferably, the synergist is one or more of plant-based polyols, piperonyl butoxide, piperonyl phosphonate, piperonyl phosphonate methyl, and octachlorodipropyl ether. More preferably, the synergist is plant-based polyols.

[0010] Preferably, the ratio of dimethyl carbonate, S-200# solvent oil and ethanol is 5:3:2.

[0011] Preferably, the ratio of the castor oil polyoxyethylene ether to the polyether phosphate salt is 1:1.

[0012] The invention provides a preparation method of spinetoram microemulsion, comprising the following steps: adding dimethyl carbonate into a stirring kettle, then adding spinetoram technical drug and stirring evenly, then adding S-200# solvent oil and ethanol and stirring until the technical drug is completely dissolved, then sequentially adding an emulsifier and a synergist and stirring to form a uniform transparent liquid, and finally supplementing the mixture with deionized water to 100%.

[0013] The present invention selects specific adjuvants to prepare microemulsion preparations with excellent performance. The present invention selects dimethyl carbonate and S-200# solvent oil as the main solvents, which have high solubility for ethyl spinetoram and good storage stability of the preparation. At the same time, the antifreeze agent ethanol also acts as a solvent, which is conducive to the dissolution of the active ingredient. Plant-based polyols, piperonyl butoxide, piperonyl phosphate, methyl piperonyl phosphate, octachlorodipropyl ether, etc. are used as synergists to significantly improve the control effect of chemical agents when preventing and controlling resistant insects such as thrips, red spiders, and aphids. Among them, the plant-based polyols are made from plant materials, can ensure crop safety, and are easily degraded in the environment. The present invention selects castor oil polyoxyethylene ether and polyether phosphate as emulsifiers, and cooperates with the above-mentioned solvents and antifreeze agents to ensure that the hot storage and cold storage stability of the microemulsion of the present invention are qualified, the decomposition rate of the active ingredient after hot storage is low, and no crystallization is precipitated after cold storage. When diluted after hot storage, a transparent and uniform liquid can be obtained without precipitation at the bottom.

[0014] By adopting the above technical solution, the present invention has the following beneficial effects:

[0015] (1) The microemulsion of the present invention is a thermodynamically stable system. The active ingredient exists stably in the form of nanoparticles. It is stable and does not delaminate during long-term storage, which does not affect the efficacy of the drug. When sprayed, it has excellent leaf wetting performance and strong leaf spreading ability.

[0016] (2) The microemulsion of the present invention can fully exert its efficacy, significantly improve the control effect of chemical agents, and at the same time ensure the safety of crops. It can effectively control resistant insects such as thrips, striped stem borers, red spiders, and aphids.

[0017] (3) The microemulsion product of the present invention is significantly superior to commercially available products in terms of heat storage and cold storage stability, formulation spreadability, rapid effectiveness and long-lasting effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 The emulsion of comparative example 1 has a fluorescent opaque pattern;

[0020] Figure 2 The emulsion of comparative example 2 is milky white;

[0021] Figure 3 This is the obvious color change picture of the sample after hot storage in comparative example 3;

[0022] Figure 4This is the precipitation diagram of the diluted emulsion of Comparative Example 4 for 1 hour;

[0023] Figure 5 This is the cold storage crystallization precipitation diagram of Comparative Example 5;

[0024] Figure 6 This is a diagram of the bottom precipitation of the diluted emulsion of Comparative Example 6 for 1 hour;

[0025] Figure 7 This is a comparison chart of dynamic surface tension between Example 2 and Comparative Example 7;

[0026] Figure 8 This is a comparison diagram of the contact angles of Example 2 and Comparative Example 7;

[0027] Figure 9 A comparison of the rolling angles of Example 2 and Comparative Example 7;

[0028] Figure 10 This is a comparison diagram of canvas wetting between Example 2 and Comparative Example 7;

[0029] Figure 11 It is a comparison chart of the wood climbing experiment of Example 2 and Comparative Example 7. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] 1. Preparation Examples

[0032] Example 1: 5% Spinetoram Microemulsion

[0033] 5% ethyl spinosad technical;

[0034] 15% dimethyl carbonate

[0035] 9% S-200# solvent oil (low naphthalene, supplier: Hualun)

[0036] 6% ethanol

[0037] 6% BY125 emulsifier (castor oil polyoxyethylene ether, emulsifier, Kaiyuan)

[0038] 12% V490 (plant-based polyol, insecticide synergist, in the formula)

[0039] 6% WINST 3737 (polyether phosphate salt, emulsifier, Keying)

[0040] Make up to 100% with deionized water.

[0041] Example 2: 10% Spinetoram Microemulsion

[0042] 10% ethyl spinosad technical;

[0043] 25% dimethyl carbonate

[0044] 15% S-200# solvent oil (low naphthalene, supplier: Hualun)

[0045] 10% ethanol

[0046] 10% BY125 emulsifier (castor oil polyoxyethylene ether, emulsifier, Kaiyuan)

[0047] 10% V490 (plant-based polyol, insecticide synergist, in the formula)

[0048] 10% WINST 3737 (polyether phosphate salt, emulsifier, Keying)

[0049] Make up to 100% with deionized water.

[0050] Example 3: 12% Spinetoram Microemulsion

[0051] 12% ethyl spinosad technical;

[0052] 26% dimethyl carbonate

[0053] 15.6% S-200# solvent oil (low naphthalene, supplier: Hualun)

[0054] 10.4% ethanol

[0055] 11% BY125 emulsifier (castor oil polyoxyethylene ether, emulsifier, Kaiyuan)

[0056] 5% V490 (plant-based polyol, insecticide synergist, in the formula)

[0057] 11% WINST 3737 (polyether phosphate salt, emulsifier, Keying)

[0058] Make up to 100% with deionized water.

[0059] The preparation method is as follows: add measured dimethyl carbonate into a stirred tank, then add ethyl spinetoram technical, stir evenly, then add S-200# solvent oil and ethanol, stir until the technical is completely dissolved, then add BY125, V490, and WINST 3737 in sequence and stir to form a uniform transparent liquid, and finally make up to 100% with deionized water.

[0060] Prepare multiple batches of samples of Examples 1-3 and test the quality control indicators. The relevant indicator testing methods are as follows:

[0061] pH value detection basis: GB / T 1601 Pesticide pH value determination method

[0062] Emulsion testing is based on: GB / T 1603 Determination of stability of pesticide emulsifiable concentrates

[0063] Persistent foaming test is based on: GB / T 28137-2011 Determination of persistent foaming properties of pesticides

[0064] Low temperature stability test is based on: GB / T 19137-2003 Determination of low temperature stability of pesticides

[0065] Thermal storage stability test is based on: GB / T 19136-2021 Determination of thermal storage stability of pesticides

[0066] The test results are shown in Table 1 below:

[0067] Table 1: Quality control index data of Examples 1-3

[0068]

[0069]

[0070] The present invention selects dimethyl carbonate and S-200# solvent oil as main solvents, which have good solubility for ethyl spinetoram. The emulsifiers castor oil polyoxyethylene ether and polyether phosphate are combined to make the preparation of the present invention have good stability, and all indicators meet the relevant requirements of microemulsion.

[0071] In microemulsions, solvents and emulsifiers, as primary adjuvants, play an important role in product stability. Only when the active ingredient is well coordinated with the solvent, emulsifier, and other adjuvants can a microemulsion product with excellent performance be prepared. To verify the adjuvant coordination of the product of the present invention, the solvent, emulsifier, and other adjuvants were replaced based on the product of Example 2, and corresponding comparative examples were prepared and subjected to stability testing. The results are summarized in Table 2 below.

[0072] As can be seen from the test data in Table 2 below, the microemulsion of Example 2 has excellent performance. It selects dimethyl carbonate and S-200# solvent oil as the main solvents, has high solubility for ethyl spinetoram, and has good storage stability of the active ingredient. At the same time, the antifreeze agent ethanol also plays a solvent role, which is conducive to the dissolution of the active ingredient. Combined with the composite emulsifier system of castor oil polyoxyethylene ether and polyether phosphate salt, the product of Example 2 has excellent heat storage stability, the decomposition rate of ethyl spinetoram is only 0.2%, and the dilution stability and cold storage stability after hot storage are qualified. Comparative Examples 1-3 do not use ethanol, Comparative Examples 2, 3, 5, and 6 use calcium dodecylbenzene sulfonate instead of polyether phosphate salt, and Comparative Examples 4-6 use S-150# solvent oil instead of S-200# solvent oil. These changes in additives all lead to a significant increase in the decomposition rate of ethyl spinetoram after hot storage, and cold storage crystallization also occurs (Comparative Example 5). When diluted after hot storage, the emulsion has fluorescent opacity or milky white (Comparative Examples 2 and 3), or bottom precipitation (Comparative Example 6).

[0073]

[0074]

[0075] Test article number: HFDL-W-YP2024-062

[0076]

[0077] When the product of Example 2 is applied, the risk to bees, silkworms, and daphnia is very high, and a protective buffer zone (such as a 500-meter isolation zone in the silkworm area) needs to be established; the risk to fish is moderate, and the concentration of the pesticide in the aquaculture area should be strictly controlled; the risk to birds, algae, earthworms, and ladybugs is relatively low, and the ecological impact is controllable under normal use.

[0078] 3. Surface tension and contact angle test

[0079] Test agent: Example 2 sample; Comparative Example 7 is a commercially available 60g / L ethyl spinosad suspension

[0080] Characterization comparison:

[0081] 1. Dynamic surface tension: The embodiment has lower surface tension, the droplets can be more evenly covered, and the droplet aggregation is reduced (see Figure 7 ).

[0082] 2. Contact angle: The contact angle of the embodiment is significantly smaller than that of the comparative example, and the spreading effect of the droplet is better (see Figure 8 ).

[0083] 3. Rolling angle: There is no significant difference between the embodiment and the comparative example (see Figure 9 ).

[0084] 4. Canvas wetting: The canvas of the embodiment and the comparative example were wetted for 3 minutes. The comparative example had almost no wetting, while the embodiment had excellent wetting effect (see Figure 10 ).

[0085] 5. Comparison of penetration effect: The embodiment and the comparative example are compared for climbing wood for 3 minutes. The embodiment is obviously better than the comparative example, and the spreading effect of the embodiment is better (see Figure 11 ).

[0086] 4. Field efficacy test

[0087] Test agents: 10% spinetoram microemulsion of Example 2, commercially available 25% spinetoram WDG, commercially available 60 g / L spinetoram SC

[0088] Targets of control: Rice stem borer, eggplant thrips

[0089] Summary of prevention and control effects:

[0090] (1) Rice stem borer:

[0091] 10% spinetoram microemulsion of Example 2:

[0092] 25 ml / mu: 7-day protection efficiency 72.67% to 79.1%.

[0093] 30 ml / mu: 7-day protection efficiency 79.89% to 83.27%.

[0094] 35 ml / mu: 7-day protection efficiency 83.26% to 91.5% (highest protection efficiency).

[0095] 25% spinetoram WDG (control): protection efficiency 78.7% to 82.76%.

[0096] 10% ethyl spinetoram microemulsion 35 ml / mu has the best control effect on the Chilo suppressalis (>90%), which is significantly better than the control agent.

[0097] (2) Eggplant thrips:

[0098] 10% spinetoram microemulsion of Example 2:

[0099] 6 ml / mu: 3-day protection effect: 79.73%-83.42%, 7-day protection effect: 79.07%-81.71%, 10-day protection effect: 71%-80.82%.

[0100] 9 ml / mu: 3-day protection effect: 77.66%~90.62%, 7-day protection effect: 82.17%~85.82%, 10-day protection effect: 78.49%~83.61%.

[0101] 12 ml / mu: 3-day protection effect: 81.49%-92.41%, 7-day protection effect: 85.08%-90.6%, 10-day protection effect: 82.74%-90.66%.

[0102] 60 g / L spinetoram SC (suspension concentrate, control): The protective effect is lower than that of the ME preparation at the same dose.

[0103] The best dosage is 12 ml / mu (active ingredient 18 g / hectare), which has the highest control effect, and the control effect is stable at 82.74% to 90.66% after 10 days.

[0104] Trend of control effect: With the extension of time after application, the control effect gradually decreased, but the decrease was smaller at high doses (12 ml / mu).

[0105] 10% ethyl spinetoram microemulsion has significant control effect on thrips at a dosage of 12 ml / mu, and the effect lasts for a long time (control effect>80% in 10 days).

[0106] Overall, the 10% spinetoram microemulsion demonstrated superior control efficacy, with both rapid-acting and sustained efficacy superior to commercially available spinetoram formulations. The control efficacy data are summarized in Tables 3 and 4 below.

[0107]

[0108]

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spinetoram microemulsion, characterized in that: Calculated by mass percentage, it contains the following components: 1-20% of ethyl spinetoram, 10-25% of emulsifier, 5-15% of synergist, 5-15% of antifreeze, 20-50% of solvent, and deionized water to make up 100%; The emulsifier is castor oil polyoxyethylene ether and polyether phosphate; the antifreeze is ethanol; and the solvent is dimethyl carbonate and S-200# solvent oil.

2. The spinetoram microemulsion according to claim 1, characterized in that: The synergist is one or more of plant-based polyols, piperonyl butoxide, piperonyl phosphate, methyl piperonyl phosphate, and octachlorodipropyl ether.

3. The spinetoram microemulsion according to claim 1, characterized in that: The ratio of dimethyl carbonate, S-200# solvent oil and ethanol is 5:3:

2.

4. The spinetoram microemulsion according to claim 1, characterized in that: The ratio of the castor oil polyoxyethylene ether to the polyether phosphate salt is 1:

1.

5. A method for preparing a spinetoram microemulsion according to any one of claims 1 to 4, comprising the following steps: After adding dimethyl carbonate to the stirring kettle, add ethyl spinetoram technical and stir evenly. Then add S-200# solvent oil and ethanol and stir until the technical is completely dissolved. Then add emulsifier and synergist in sequence and stir into a uniform transparent liquid. Finally, add deionized water to 100%.

6. Use of the spinetoram microemulsion according to any one of claims 1 to 4 in controlling crop pests.

7. Use of the spinetoram microemulsion according to claim 6 in preventing and controlling crop pests, characterized in that: The crop pest is the rice stem borer or the eggplant thrips.

Images