An ethyl spinosyn microemulsion, its preparation method and application

Abstract

The present application provides a kind of ethyl spinosyn microemulsion and its preparation method and application.The microemulsion of the present application belongs to thermodynamic stable system, and the active ingredient exists in the form of nanoscale particles, is stable, does not separate for a long time storage, does not affect the play of drug efficacy, when spraying, leaf surface wetting performance is excellent, and leaf surface spreading ability is strong.The microemulsion of the present application can fully exert the efficacy, significantly improve the prevention and control effect of chemical agent, while ensuring the safety of crops, can effectively prevent and control thrips, chilo, red spider, aphid and other resistant insects.

Description

Technical Field

[0001] This invention relates to the field of pesticide formulation technology, and in particular to an ethyl spinosad microemulsion, its preparation method, and its application. Background Technology

[0002] Pesticide formulations come in various types, mainly including wettable powders, emulsifiable concentrates, granules, suspension concentrates, and microemulsions. With increasingly stringent environmental policies, pesticide formulations are rapidly shifting towards water-based formulations. Water-based formulations (such as microemulsions and water-in-oil emulsions) use water to replace organic solvents, reducing volatile organic compound (VOC) emissions and lowering environmental pollution and flammability risks.

[0003] Pesticide microemulsions (ME) are thermodynamically stable dispersion systems with water as the continuous phase. They consist of liquid pesticide technical (or solid technical dissolved in organic solvents), surfactants, co-surfactants, and water, forming a transparent or semi-transparent homogeneous liquid with a particle size of 0.01-0.1 μm. Pesticide microemulsions are environmentally friendly, safe, highly efficient in penetration, highly stable, and have low toxicity and low residue, making them a mainstream alternative to emulsifiable concentrates.

[0004] Spinetoram is a novel bio-based insecticide developed by Dow AgroSciences (now Corteva) through chemical modification of spinosad. It belongs to the second-generation spinosad class of insecticides. Spinetoram has low solubility in water but is readily soluble in organic solvents such as methanol and acetone. It degrades rapidly under light, has a short half-life in soil, and has minimal environmental impact. Ethyl spinosad has contact and stomach poison effects. It acts on the nicotinic acetylcholine receptors (nAChR) and gamma-aminobutyric acid receptors (GABA) in the insect nervous system, interfering with signal transduction and causing paralysis and death. Its activity is 10 times that of spinosad. It is effective against Lepidoptera, Thysanoptera, and Diptera pests, including rice stem borer, rice leaf roller, rice thrips, diamondback moth, beet armyworm, cotton bollworm, bean pod borer, American serpentine 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 ethyl spinosad include suspension concentrates and water-dispersible granules.

[0005] The widely used 60g / L ethyl spinosad suspension is a thermodynamically unstable system. Long-term storage can easily cause phenomena such as crusting and layering, which affect its use. There are also differences between batches of products, which leads to unstable efficacy.

[0006] Existing technologies disclose various pesticide formulations containing ethyl spinosad, such as CN101874486A, CN102246799A, and CN102396487A. However, these patent applications all focus on the synergistic effect of ethyl spinosad combined with other pesticide active ingredients. Moreover, although some patent applications disclose their microemulsion formulations and related formulas, none of them have conducted quality index testing or toxicological experiments. It is unclear whether they can actually prepare qualified ethyl spinosad microemulsion products. Summary of the Invention

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

[0008] The emulsifier is castor oil polyoxyethylene ether and polyether phosphate salt; the synergist is one or more of plant-based polyols, synergist ethers, synergist phosphorus, methyl synergist phosphorus, 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 selected from plant-based polyols, synergistic ethers, synergistic phosphorus, methyl synergistic phosphorus, and octachlorodipropyl ether. More preferably, the synergist is a plant-based polyol.

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

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

[0012] This invention provides a method for preparing ethyl spinosad microemulsion, comprising the following steps: adding dimethyl carbonate to a stirred tank, then adding ethyl spinosad technical and stirring until uniform; then adding S-200# solvent oil and ethanol and stirring until the technical is completely dissolved; then adding emulsifier and synergist in sequence and stirring to form a uniform transparent liquid; and finally adding deionized water to make up to 100%.

[0013] This invention selects specific adjuvants to formulate a high-performance microemulsion. Dimethyl carbonate and S-200# solvent oil are chosen as the main solvents, exhibiting high solubility for ethyl spinosad and good storage stability. Simultaneously, the antifreeze ethanol also acts as a solvent, facilitating the dissolution of the active ingredient. Plant-based polyols, synergistic ethers, synergistic phosphorus, methyl synergistic phosphorus, and octachlorodipropyl ether are used as synergists, significantly improving the control efficacy of chemical pesticides against resistant insects such as thrips, spider mites, and aphids. The plant-based polyols, made from plant materials, ensure crop safety and are easily degraded in the environment. Castor oil polyoxyethylene ether and polyether phosphate salts are selected as emulsifiers. Combined with the aforementioned solvents and antifreeze, this invention ensures satisfactory heat and cold storage stability of the microemulsion, with low decomposition rate of the active ingredient after heat storage and no crystallization after cold storage. Upon dilution after heat storage, a transparent and uniform solution is obtained without sediment at the bottom.

[0014] By adopting the above technical solution, the present invention has the following beneficial effects: (1) The microemulsion of this invention belongs to a thermodynamically stable system. The active ingredients exist stably in the form of nano-sized particles. It is stable and does not separate into layers during long-term storage, and does not affect the efficacy. When used as a spray, it has excellent leaf wetting performance and strong leaf spreading ability.

[0015] (2) The microemulsion of the present invention can fully exert the efficacy of the drug, 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, rice stem borers, spider mites, and aphids.

[0016] (3) The microemulsion products of the present invention are significantly superior to commercially available products in terms of heat and cold storage stability, formulation spreading ability, rapid efficacy and sustained efficacy. Attached Figure Description To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 The image shows the fluorescent opacity of the emulsion in Comparative Example 1. Figure 2 The image shows the milky white color of the emulsion in Comparative Example 2. Figure 3 This is a diagram showing the obvious color change of the sample in Comparative Example 3 after heat storage; Figure 4 The graph shows the precipitation of the diluted emulsion in Comparative Example 4 after 1 hour. Figure 5 This is a precipitation diagram of the cold storage crystallization in Comparative Example 5; Figure 6 The graph shows the sedimentation at the bottom of the diluted emulsion in Comparative Example 6 after 1 hour. Figure 7 This is a comparison diagram of the dynamic surface tension between Example 2 and Comparative Example 7; Figure 8 This is a comparison diagram of the contact angles of Example 2 and Comparative Example 7; Figure 9 This is a comparison diagram of the roll angles of Example 2 and Comparative Example 7; Figure 10 This is a comparison diagram of canvas wetting between Example 2 and Comparative Example 7; Figure 11 This is a comparison diagram of the tree climbing experiments of Example 2 and Comparative Example 7. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] I. Formulation Examples Example 1: 5% Ethyl Spinosad Microemulsion 5% spinosad technical grade; 15% dimethyl carbonate 9% S-200# solvent oil (low naphthalene, supplier: Hualun) 6% ethanol 6% BY125 emulsifier (castor oil polyoxyethylene ether, emulsifier, Kaiyuan) 12%V490 (Plant-based polyol, insecticide synergist, in the formula) 6% WINST 3737 (Polyether phosphate salt, emulsifier, Keying) Add deionized water to bring the total to 100%.

[0020] Example 2: 10% Ethyl Spinosad Microemulsion 10% spinosad technical grade; 25% dimethyl carbonate 15% S-200# solvent oil (low naphthalene, supplier: Hualun) 10% ethanol 10% BY125 emulsifier (castor oil polyoxyethylene ether, emulsifier, Kaiyuan) 10%V490 (Plant-based polyol, insecticide synergist, in the formula) 10% WINST 3737 (polyether phosphate salt, emulsifier, Keying) Add deionized water to bring the total to 100%.

[0021] Example 3: 12% Ethyl Spinosad Microemulsion 12% spinosad technical grade; 26% dimethyl carbonate 15.6% S-200# solvent oil (low naphthalene, supplier: Hualun) 10.4% ethanol 11% BY125 emulsifier (castor oil polyoxyethylene ether, emulsifier, Kaiyuan) 5%V490 (plant-based polyol, insecticide synergist, in the formula) 11% WINST 3737 (Polyether phosphate salt, emulsifier, Keying) Add deionized water to bring the total to 100%.

[0022] The preparation method is as follows: Add the measured amount of dimethyl carbonate to the stirred tank, then add the ethyl spinosad technical material, stir evenly, then add S-200# solvent oil and ethanol, stir until the technical material is completely dissolved, then add BY125, V490 and WINST 3737 in sequence and stir into a uniform transparent liquid, and finally add deionized water to make up to 100%.

[0023] Multiple batches of samples from Examples 1-3 were prepared, and quality control indicators were tested. The relevant testing methods are as follows: pH value testing is based on: GB / T 1601 Method for Determination of pH Value of Pesticides Emulsion testing is based on: GB / T 1603 Determination of stability of pesticide emulsifiable concentrates. The test standard for persistent foaming properties is GB / T 28137-2011, "Determination of Persistent Foaming Properties of Pesticides". Low-temperature stability testing is based on: GB / T 19137-2003 Methods for Determination of Low-Temperature Stability of Pesticides The test standard for thermal storage stability is GB / T 19136-2021, which specifies the test method for thermal storage stability of pesticides. The test results are shown in Table 1 below: Table 1: Quality Control Index Data for Examples 1-3

[0024] This invention selects dimethyl carbonate and S-200# solvent oil as the main solvents, which have good solubility for ethyl spinosad. Combined with emulsifiers castor oil polyoxyethylene ether and polyether phosphate salt, the formulation of this invention has good stability, and all indicators meet the relevant requirements of microemulsions.

[0025] In microemulsions, solvents and emulsifiers, as key additives, play a crucial role in product stability. Only when the active ingredient is well-matched with the solvent, emulsifier, and other additives can a high-performance microemulsion product be prepared. To verify the additive compatibility of the product of this invention, solvents, emulsifiers, and other additives were replaced based on the product of Example 2 to obtain corresponding comparative samples, and stability tests were performed. The results are summarized in Table 2 below.

[0026] As can be seen from the experimental data in Table 2 below, the microemulsion of Example 2 exhibits excellent performance. It uses dimethyl carbonate and S-200# solvent oil as the main solvents, resulting in high solubility of ethyl spinosad and good storage stability of the active ingredient. Simultaneously, the antifreeze ethanol also acts as a solvent, facilitating 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 demonstrates excellent thermal storage stability, with an ethyl spinosad decomposition rate of only 0.2%. Its dilution stability after thermal storage and its cold storage stability are also satisfactory. Comparative Examples 1-3 did not use ethanol; Comparative Examples 2, 3, 5, and 6 used calcium dodecylbenzenesulfonate instead of polyether phosphate salt; and Comparative Examples 4-6 used S-150# solvent oil instead of S-200# solvent oil. These changes in additives all led to a significant increase in the ethyl spinosad decomposition rate after thermal storage, and also resulted in crystallization precipitation during cold storage (Comparative Example 5). After thermal storage, the emulsion exhibited fluorescence and opacity or appeared milky white upon dilution (Comparative Examples 2 and 3), or bottom precipitation (Comparative Example 6).

[0027] Table 2: Formulation and stability data of Examples 2 and Comparative Examples 1-6

[0028] II. Toxicological Experiments: Testing Unit: Zhejiang Yangtze River Delta Chemical Safety Assessment Co., Ltd. Test reagent: 10% spinosad microemulsion from Example 2 Acute oral toxicity: The LD50 in female rats was 3129 mg / kg, indicating low toxicity.

[0029] Acute dermal toxicity: Rat LD50 (male / female) > 2000 mg / kg, low toxicity.

[0030] Eye irritation test: The skin irritation to rabbit eyes was moderate.

[0031] Eye wash test: 7 days after administration, all tested eyes showed no irritation and fully recovered.

[0032] Skin irritation test: No irritation to rabbit skin. Observations were conducted at 1 h, 24 h, 48 h, and 72 h after removal of the test substance. No erythema or edema was observed in the test and control areas of any animals, and no systemic reactions were observed. The highest average score for skin irritation at the 24 h, 48 h, and 72 h observation points was 0.

[0033] Sensitization test: No skin allergic reaction was observed in guinea pigs. The sensitization rate was 0%.

[0034]

[0035] Example 2: The product poses a high risk to bees, silkworms, and daphnia when applied, requiring the establishment of a protective buffer zone (such as a 500-meter isolation zone in silkworm areas); it poses a medium risk to fish, and the concentration of the drug in aquaculture areas should be strictly controlled; it poses a low risk to birds, algae, earthworms, and ladybugs, and the ecological impact is controllable under normal use.

[0036] III. Surface Tension and Contact Angle Tests Test reagents: Sample from Example 2; Comparative Example 7 was commercially available 60 g / L spinosad suspension concentrate. Characteristic comparison: 1. Dynamic surface tension: The embodiment has lower surface tension, allowing for more uniform droplet coverage and reducing droplet aggregation (see [reference]). Figure 7 ).

[0037] 2. Contact Angle: The contact angle of the embodiment is significantly smaller than that of the comparative example, resulting in better droplet spreading (see [reference]). Figure 8 ).

[0038] 3. Roll-off angle: There is no significant difference between the example and the comparative example (see Figure 9 ).

[0039] 4. Canvas Wetting: Comparing the canvas wetting of the example and the comparative example for 3 minutes, the comparative example showed almost no wetting, while the example demonstrated excellent wetting effect (see [reference]). Figure 10 ).

[0040] 5. Comparison of penetration effect: Comparing the 3-minute penetration test results of the example and the comparative example, the example is significantly better than the comparative example, and the spreading effect of the example is better (see...). Figure 11 ).

[0041] IV. Field efficacy trials Test reagents: 10% spinosad microemulsion from Example 2, commercially available 25% spinosad WDG, and commercially available 60 g / L spinosad SC. Target pests: Rice stem borer, eggplant thrips Summary of prevention and control effects: (1) Rice stem borer: Example 2: 10% Ethyl Spinosad Microemulsion 25 ml / mu: 72.67%~79.1% control efficacy in 7 days.

[0042] 30 ml / mu: 79.89%~83.27% control efficacy in 7 days.

[0043] 35 ml / mu: 7-day control efficacy of 83.26%~91.5% (maximum control efficacy).

[0044] 25% spinosad WDG (control): efficacy 78.7%~82.76%.

[0045] The 10% spinosad microemulsion at 35 ml / acre showed the best control efficacy against rice stem borer (>90%), which was significantly better than the control agent.

[0046] (2) Eggplant thrips: Example 2: 10% Ethyl Spinosad Microemulsion 6 ml / mu: 79.73%~83.42% control efficacy in 3 days, 79.07%~81.71% control efficacy in 7 days, and 71%~80.82% control efficacy in 10 days.

[0047] 9 ml / mu: 3-day efficacy 77.66%~90.62%, 7-day efficacy 82.17%~85.82%, 10-day efficacy 78.49%~83.61%.

[0048] 12 ml / mu: 3-day efficacy 81.49%~92.41%, 7-day efficacy 85.08%~90.6%, 10-day efficacy 82.74%~90.66%.

[0049] 60 g / L spinosad SC (suspension, control): lower efficacy than ME formulation at the same dose.

[0050] The optimal dosage is 12 ml / mu (18 g of active ingredient / ha) for the highest control efficacy, with the control efficacy stabilizing at 82.74%~90.66% after 10 days.

[0051] Efficacy trend: The efficacy gradually decreases with the extension of time after application, but the decrease is smaller at high doses (12 ml / acre).

[0052] 10% spinosad microemulsion showed significant efficacy against thrips at a dose of 12 ml / acre, with a long duration of effect (10-day efficacy >80%).

[0053] Overall, the 10% spinosad microemulsion showed superior control efficacy, with both faster and longer-lasting effects compared to commercially available spinosad formulations. Efficacy data are summarized in Tables 3 and 4 below.

[0054] Table 3

[0055] Table 4

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions 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. An ethyl spinosad microemulsion, characterized in that, By weight percentage, it contains the following components: 1-20% ethyl spinosad, 10-25% emulsifier, 5-15% synergist, 5-15% antifreeze, 20-50% solvent, and deionized water to make up to 100%; The emulsifiers are castor oil polyoxyethylene ether BY125 emulsifier and polyether phosphate salt WINST 3737. The antifreeze is ethanol; the solvent is dimethyl carbonate and S-200# solvent oil. The synergist is a plant-based polyol; The ratio of dimethyl carbonate, S-200# solvent oil and ethanol is 5:3:2; The ratio of castor oil polyoxyethylene ether to polyether phosphate salt is 1:

1.

2. The preparation method of an ethyl spinosad microemulsion according to claim 1, comprising the following steps: Add dimethyl carbonate to the stirred tank, then add ethyl spinosad technical grade and stir until homogeneous. Then add S-200# solvent oil and ethanol and stir until the technical grade is completely dissolved. Then add emulsifier and synergist in sequence and stir until a uniform and transparent liquid is formed. Finally, add deionized water to make up to 100%.

3. The application of the ethyl spinosad microemulsion according to claim 1 in the control of crop pests.

4. The application of the ethyl spinosad microemulsion according to claim 3 in the control of crop pests, characterized in that, The crop pests mentioned are rice stem borer or eggplant thrips.

Images