A microemulsion of pyraclostrobin and epoxiconazole, and its preparation method and application

Abstract

The present invention relates to the technical field of pesticides, specifically to a pyraclostrobin and epoxiconazole microemulsion and a preparation method and application thereof, which comprises, by weight percentage: 2-15% of pyraclostrobin, 1-6% of epoxiconazole, 8%-30% of a polyoxyethylene ether emulsifier, 1-5% of a block polyether nonionic surfactant, 15-45% of a solvent, 3-15% of a cosolvent, 0.005-0.05% of a defoamer, and deionized water supplemented to 100%. By using pyraclostrobin and epoxiconazole as effective active ingredients, under the action of specific polyoxyethylene ether emulsifiers, block polyether nonionic surfactants, solvents, and cosolvents, the prepared microemulsion has the effects of protection, treatment, and leaf penetration and conduction, can better prevent and treat corn leaf blight, can also reduce the dosage, and delay and control the drug resistance of pathogens.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, in particular to a pyraclostrobin and epoxiconazole microemulsion and a preparation method and application thereof. Background Art

[0002] Pyraclostrobin was first successfully developed by BASF in Germany in 1993, reported to the public in 2000, and registered and marketed in 2001 as 250 g / L pyraclostrobin emulsifiable concentrate. The single and mixed preparations of pyraclostrobin registered in my country mainly come from BASF Europe and Guangdong Deli Biotechnology Co., Ltd. It is widely used to prevent and control diseases caused by almost all types of fungal pathogens such as ascomycetes, basidiomycetes, deuteromycetes and oomycetes on cereals, soybeans, tea trees, peanuts, cotton, grapes, vegetables, potatoes, sunflowers, bananas, lemons, coffee, fruit trees, walnuts, tea trees, tobacco, ornamental plants, lawns and other field crops. It can also be used for seed treatment. According to data from the China Pesticide Information Network, as of January 2022, there are 711 pyraclostrobin products registered in my country, including 294 single agents and 417 mixed preparations. Registered dosage forms include technical, suspension, wettable powder, seed treatment suspension, emulsion, etc. The main registered crops are apple trees, cucumbers, bananas and strawberries.

[0003] Fluepoxiconazole is a new, broad-spectrum, long-lasting fungicide developed by BASF in 1985. In early 1993, fluepoxiconazole first entered the French market under the trade name Opus, and then entered Europe, South America and Asia. Fluepoxiconazole was first registered by BASF AG of Germany in 2000. Subsequently, Jiangsu Gengyun Chemical Co., Ltd., Jiangsu Feixiang Chemical Co., Ltd., and the Pilot Plant of Shenyang Institute of Chemical Technology of Liaoning Province were registered in 2005, and Shanghai Shengnong Biochemical Products Co., Ltd. and Jiangsu Zhongqi Chemical Co., Ltd. were registered in 2006. According to data from the China Pesticide Information Network, as of November 2020, there were 208 fluepoxiconazole products registered in my country, including 109 single agents and 99 mixtures. The dosage forms include technical, water-dispersible granules, suspensions and emulsifiable concentrates. The main registered crops are bananas, rice and wheat.

[0004] The prior art improves the efficacy of a single drug by compounding the drug. For example, a Chinese patent application (publication number CN113575604A) discloses an aqueous suspension containing pyraclostrobin and epoxiconazole and a preparation method thereof. Specifically, pyraclostrobin and epoxiconazole are used as the main active ingredients, and a rehydrated suspension is prepared in the presence of other adjuvants. The suspension has good dispersibility, good storage stability, high efficacy and long lasting effect. However, the suspension is not conducive to adhesion and spread on crops, insect bodies and pathogens, and the utilization rate of the pesticide is low. A Chinese patent application (publication number CN114651822A) provides a composition, a drug and its use in the prevention and treatment of citrus anthracnose. Specifically, epoxiconazole and pyraclostrobin are used as active ingredients in a mass ratio of (2 to 16):1, so that the provided product is used for the prevention and treatment of acute citrus anthracnose. However, the research on the prevention and treatment effects of corn leaf blight, wheat powdery mildew and scab is not involved. Summary of the invention

[0005] In one aspect of the present invention, a pyraclostrobin and epoxiconazole microemulsion comprises, by weight percentage, 2-15% of pyraclostrobin, 1-6% of epoxiconazole, 8%-30% of a polyoxyethylene ether emulsifier, 1-5% of a block polyether nonionic surfactant, 15-45% of a solvent, 3-15% of a cosolvent, 0.005-0.05% of a defoamer, and deionized water supplemented to 100%.

[0006] As a preferred technical solution, the mass ratio of pyraclostrobin to epoxiconazole is (1-5):1; preferably, the mass ratio of pyraclostrobin to epoxiconazole is (2-3):1.

[0007] The inventors found in the actual research and development process that when pyraclostrobin and fluphenazine were used as the effective active ingredients to prepare a suspension for subsequent application, it was found that after the sample was placed at room temperature for 24 hours after hot storage, pyraclostrobin was very easy to melt and crystals precipitated from the formula system. Although the formula cost of the suspension was low, the surface tension of the liquid after dilution (2000 times dilution) was too large, and the spreading ability on crops was not good enough. Compared with other dosage forms, the efficacy was not competitive enough. The existing commercially available products had the problem of unqualified pass rate in the wet screening test after hot storage, and there was a large amount of colloid residue on the sieve, and the particle size of the product increased seriously.

[0008] Based on the system of the present invention, pyraclostrobin and epoxiconazole are used as effective active ingredients. Under the action of specific polyoxyethylene ether emulsifiers, block polyether nonionic surfactants, solvents, and cosolvents, the prepared microemulsion has protective, therapeutic, and leaf penetration and conduction effects, can better prevent and treat corn leaf blight, and can also reduce the dosage, delay and control the drug resistance of pathogens. The inventor analyzed that the reason may be: pyraclostrobin is a quinone external inhibitor, which inhibits mitochondrial respiration by blocking the electron transfer of the cytochrome bc1 complex, thereby achieving a bactericidal effect, while epoxiconazole can effectively inhibit pathogenic fungi, increase the chitinase activity of crops, lead to the contraction of fungal haustoria, inhibit the invasion of pathogens, and have both protective and therapeutic effects. The two have obvious synergistic effects through two different modes of action, achieve complementary advantages, and alleviate the generation of pest resistance. The inventors explored the co-toxicity coefficient of the combination of pyraclostrobin and epoxiconazole for corn leaf blight, and found that, especially when the mass ratio of pyraclostrobin and epoxiconazole introduced in the system was (2-3): 1, the synergistic effect of pyraclostrobin and epoxiconazole was the most significant, and it had the highest co-toxicity coefficient when used to prevent and treat corn leaf blight, which could effectively reduce the amount of pesticide used and agricultural cost, and it was highly effective, low in toxicity and low in residue, providing a choice for preventing and treating agricultural pests. In addition, the preparation of microemulsions has low organic solvent dosage, high surfactant dosage, high original drug utilization rate, reduced environmental pollution, low surface tension (2000 times dilution), good spreadability, and can promote the penetration of the original drug into the internal tissues of animals and plants, improve the transfer efficiency, convenient production, stable state, homogeneous stability at the use concentration, and safe transportation and storage.

[0009] As a preferred technical solution, the polyoxyethylene ether emulsifier is at least one of aromatic phenol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, castor oil polyoxyethylene ether, phenolic resin polyoxyethylene ether, fatty alcohol polyoxypropylene ether, nonylphenol formaldehyde condensate polyoxyethylene ether, and diphenylethyl phenol formaldehyde condensate polyoxyethylene ether; preferably, the polyoxyethylene ether emulsifier is a combination of aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and diphenylethyl phenol formaldehyde condensate polyoxyethylene ether.

[0010] Preferably, the aromatic phenol polyoxyethylene ether is at least one of tristyrylphenol polyoxyethylene ether, dibenzylbiphenol polyoxyethylene ether, dibenzylphenol polyoxyethylene ether, isopropylphenylethylphenol polyoxyethylene ether, and dibenzylphenol polyoxyethylene ether; most preferably, the aromatic phenol polyoxyethylene ether is tristyrylphenol polyoxyethylene ether.

[0011] Preferably, the fatty alcohol polyoxyethylene ether is at least one of C16-18 fatty alcohol polyoxyethylene ether, isomeric decanol polyoxyethylene ether, isomeric tridecanol polyoxyethylene ether, and lauryl alcohol polyoxyethylene ether; preferably, the fatty alcohol polyoxyethylene ether is isomeric tridecanol polyoxyethylene ether.

[0012] As a preferred technical solution, the block polyether type nonionic surfactant is a propylene glycol block polyether; preferably, the model of the propylene glycol block polyether is at least one of polyether 2040, L31, L42, L43, L61, L62, L64, L68, and L81; further preferably, the HLB value of the propylene glycol block polyether is 7-13; the average molecular weight of the propylene glycol block polyether is 2500-2900; most preferably, the propylene glycol block polyether is a combination of L62 and L64; the mass ratio of L62 to L64 is (1-2): (1.5-3). The L62 and L64 are sourced from Liaoning Kelong Fine Chemical Co., Ltd.

[0013] During the research process, the inventors found that the compounding effect and system stability of aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, diphenylethyl phenol formaldehyde condensate polyoxyethylene ether and propylene glycol block polyether introduced into the system were greatly affected by propylene glycol block polyether, which in turn led to the synergistic efficacy of pyraclostrobin and fluphenazine not being fully exerted. Based on the tristyrylphenol polyoxyethylene ether, isomeric tridecanol polyoxyethylene ether and diphenylethylphenol formaldehyde condensate polyoxyethylene ether in the system of the present invention, a block polyether type nonionic surfactant propylene glycol block polyether is introduced, especially L62 and L64 with a mass ratio of (1-2): (1.5-3) are introduced for use in combination, mixed micelles are formed in the system, the emulsification effect is improved to the greatest extent to ensure the stability of the system, and at the same time, the provided microemulsion has good efficacy and a long lasting effect. The inventor analyzed that the reason may be: the introduction of L62 and L64 with a mass ratio of (1-2): (1.5-3) achieves good matching and synergistic effect with the aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and diphenylethylphenol formaldehyde condensate polyoxyethylene ether in the system, which is beneficial to the adhesion and spread of pyraclostrobin and fluphenazine on crops and pathogens, significantly improves the deposition effect of the application and the utilization efficiency of the pesticide, makes the provided microemulsion less susceptible to the influence of environmental humidity and temperature, and achieves long-lasting and effective prevention and control. In addition, the inventors unexpectedly discovered that by introducing L62 and L64 in a mass ratio of (1-2): (1.5-3), the emulsification effect was improved, avoiding the milky white unqualified state of the preparation after being diluted 200 times with water due to the excessive particle size of the emulsified droplets entering the water, and making the provided preparation transparent and with blue fluorescence after being diluted 200 times with water. The inventors analyzed that the possible reasons are: during the use of the preparation sample in water, different water entry states lead to large differences in the dilution and dispersion effects of the preparation. Direct high dilution multiple dilution of the surfactant in water has a low concentration and is effectively dispersed in a molecular state. In the process of first mixing the preparation sample and water in a 1:1 ratio, the surfactant concentration is much higher than its critical micelle concentration, causing the surfactant molecules to combine into large groups to form micelles. Further dilution with water cannot effectively disperse the surfactant and it appears milky white and unqualified. The introduction of a combination of L62 and L64 propylene glycol block polyethers in a mass ratio of (1-2): (1.5-3) effectively increases the critical micelle concentration of the system, allowing it to be quickly and effectively dispersed under high concentration dilution conditions, and can make the diluted solution transparent and have blue fluorescence (in a nanometer state).

[0014] As a preferred technical solution, the mass ratio of the aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, diphenylethylphenol formaldehyde condensate polyoxyethylene ether, and propylene glycol block polyether is (6-10): (7-9): (5-10): (2-5).

[0015] Most products on the market are in good condition when used alone at a low concentration of more than 1000 times dilution, but the actual use of pesticides is often accompanied by the mixing of pesticides and fertilizers, and the mixing of multiple components of other pesticides. With the development of aerial spraying technology, pesticides are required to be used at a dilution of 20 to 50 times, and the water hardness in different regions is also very different. This leads to the actual application of pesticides in a high electrolyte system. Many pesticide preparations have insufficient electrolyte resistance and cannot maintain homogeneous and stable dispersion in this system. During use, flocculation, stratification, paste, and even agglomeration will occur, blocking the nozzle filter of the aircraft. The inventor found in the process of exploration that the introduction of tristyrylphenol polyoxyethylene ether and isomeric tridecanol polyoxyethylene ether into the system effectively improves the emulsification state of the preparation into water, and effectively enhances the surface permeability and systemicity of crops and pathogens. However, in the actual application exploration of aerial spraying with high-concentration mixing of potassium dihydrogen phosphate, it was found that the product had stratification and demulsification, which directly led to the inability of the product to effectively and evenly act on the receptor, greatly reducing the utilization rate and disease control effect of pyraclostrobin and fluphenazine. The inventors introduced polyoxyethylene ether of diphenylethyl phenol formaldehyde condensate and propylene glycol block polyether to make the finally prepared microemulsion have significantly improved electrolyte resistance, and can be mixed with common foliar fertilizers, potassium dihydrogen phosphate, wettable powders, etc. on the market in a 1:1 ratio and still maintain homogeneous stability when diluted 20 times. The inventors analyzed that the possible reason is that after tristyrylphenol polyoxyethylene ether comes into contact with a high concentration of potassium dihydrogen phosphate electrolyte, the mixed CMC micelles are changed, resulting in demulsification and stratification. The introduction of diphenylethylphenol formaldehyde condensate polyoxyethylene ether and propylene glycol block polyether, while controlling the mass ratio of the aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, diphenylethylphenol formaldehyde condensate polyoxyethylene ether, and propylene glycol block polyether to be (6-10): (7-9): (5-10): (2-5), can, on the one hand, produce a synergistic effect with tristyrylphenol polyoxyethylene ether and isomeric tridecanol polyoxyethylene ether in the system, further improve the stability of the system, enhance the protective effect on crops, and reduce irritation; on the other hand, it significantly improves the electrolyte resistance of the microemulsion formula system, avoids stratification and demulsification failure after contact with high concentration of potassium dihydrogen phosphate, and meets the application scenario of aerial defense.

[0016] As a preferred technical solution, the solvent is at least one of dimethylpropionamide, dimethylformamide, and dimethyl carbonate; preferably, the solvent is a combination of dimethyl carbonate and dimethylpropionamide; the mass ratio of dimethyl carbonate to dimethylpropionamide is (0.8-1.2):1.

[0017] As a preferred technical solution, the co-solvent is cyclohexanone;

[0018] The inventors found in the actual production and development process that when the low-temperature stability test of the preparation was carried out according to the GB / T 19137-2003 pesticide low-temperature stability determination method, it was found that the preparation had a problem of crystal precipitation during the 7-day cold storage at 0°C. Based on the system of the present invention, by using a combination of dimethyl carbonate and dimethylpropionamide in a mass ratio of (0.8-1.2):1 as a solvent, and introducing cyclohexanone as a co-solvent, the pyraclostrobin and flufenoxazole in the system are fully mixed and compatible, ensuring the subsequent emulsification and dispersion effect, and effectively improving the cold and hot storage stability of the preparation. The improved preparation still remains homogeneous, clear and transparent after storage at -6°C for 30 days, and no crystal precipitation occurs.

[0019] Another aspect of the present invention provides a method for preparing a microemulsion of pyraclostrobin and epoxiconazole:

[0020] (1) Add the cosolvent and solvent into the preparation kettle, turn on the stirrer, add pyraclostrobin and epoxiconazole, stir, dissolve and mix for 30-60 minutes;

[0021] (2) accurately weighing the polyoxyethylene ether emulsifier, the block polyether nonionic surfactant, and the defoamer according to the feeding ratio and sequentially adding them into the preparation kettle, turning on the stirrer to mix for 30-60 minutes;

[0022] (3) Add deionized water into the preparation kettle and mix for 30-60 minutes.

[0023] The third aspect of the present invention provides an application of a microemulsion of pyraclostrobin and epoxiconazole for the prevention and treatment of corn leaf blight, wheat powdery mildew and fusarium head blight.

[0024] Beneficial Effects

[0025] 1. The present invention provides a pyraclostrobin and epoxiconazole microemulsion, which uses pyraclostrobin and epoxiconazole as effective active ingredients. Under the action of specific polyoxyethylene ether emulsifiers, block polyether nonionic surfactants, solvents, and cosolvents, the prepared microemulsion has protective, therapeutic, and leaf penetration and conduction effects, can effectively prevent and control corn leaf blight, and can also reduce the dosage of the drug, delay and control the drug resistance of pathogens.

[0026] 2. Based on the system of the present invention, by introducing diphenylethyl phenol formaldehyde condensate polyoxyethylene ether and propylene glycol block polyether, and controlling the mass ratio of the aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, diphenylethyl phenol formaldehyde condensate polyoxyethylene ether, and propylene glycol block polyether to be (6-10): (7-9): (5-10): (2-5), the microemulsion finally prepared has significantly improved electrolyte resistance, can be mixed with common foliar fertilizers, potassium dihydrogen phosphate, wettable powders, etc. on the market in a 1:1 ratio, and can still maintain homogeneous stability when diluted 20 times, meeting the application scenario of aerial spraying; at the same time, the protective effect on crops is improved and the irritation is reduced.

[0027] 3. Based on the system of the present invention, a block polyether nonionic surfactant propylene glycol block polyether is introduced, especially L62 and L64 with a mass ratio of (1-2): (1.5-3) are introduced for use in combination, and mixed micelles are formed in the system to maximize the emulsification effect and ensure the stability of the system, so that the provided preparation is transparent and has blue fluorescence when diluted 200 times into water, and at the same time, the provided microemulsion has good efficacy and a long lasting effect.

[0028] 4. Based on the system of the present invention, by using a combination of dimethyl carbonate and dimethylpropionamide in a mass ratio of (0.8-1.2): 1 as a solvent, and introducing cyclohexanone as a co-solvent, the pyraclostrobin and fluopicolide in the system are fully mixed and compatible, ensuring the subsequent emulsification and dispersion effect, and effectively improving the cold and hot storage stability of the preparation. The improved preparation remains homogeneous, clear and transparent after storage at -6°C for 30 days, and no crystal precipitation occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 These are the test results of the physical and chemical properties of the pyraclostrobin and epoxiconazole microemulsions prepared in Example 1 of the present invention.

[0030] Figure 2 The present invention provides the toxicity test method and results of pyraclostrobin and epoxiconazole and their mixtures in the ratio of 1:1, 2:1, 3:1, 4:1 and 5:1 against Setosphaeria zea maydis.

[0031] Figure 3 This is a field efficacy test report on the pyraclostrobin and fluphenazine microemulsion prepared in Example 1 of the present invention for controlling corn leaf blight.

[0032] Figure 4 This is a field efficacy test report on the pyraclostrobin and epoxiconazole microemulsions prepared in Example 1 of the present invention for controlling wheat fusarium head blight.

[0033] Figure 5 This is a comparison chart of the surface tension results of Example 1 of the present invention and Comparative Example 1 after dilution 2000 times, wherein (a) is Example 1, and (b) is Comparative Example 1.

[0034] Figure 6 1 is a comparison chart of the low temperature stability test results of Example 1 and Comparative Example 2 of the present invention, wherein (a) is Comparative Example 2, and (b) is Example 1.

[0035] Figure 7 1 is a comparison chart of the hot storage stability test results of Example 1 and Comparative Example 3 of the present invention, wherein (a) is Comparative Example 3, and (b) is Example 1.

[0036] Figure 8 The following is a comparison chart of the test results of 200-fold dilution into water of Example 1 and Comparative Example 4 of the present invention, wherein (a) is Comparative Example 4, and (b) is Example 1.

[0037] Fig. 9 This is a comparison chart of the test results of Example 1 and Comparative Example 5 of the present invention and 20-fold diluted potassium dihydrogen phosphate, wherein (a) is Comparative Example 5, and (b) is Example 1. DETAILED DESCRIPTION

[0038] Example 1

[0039] Embodiment 1 of the present invention is a pyraclostrobin and fluconazole microemulsion, which comprises, by weight percentage: 12.3% of pyraclostrobin, 4.7% of fluconazole, 22% of polyoxyethylene ether emulsifier, 3% of block polyether nonionic surfactant, 20% of solvent, 5% of cosolvent, 0.01% of defoamer, and deionized water is supplemented to 100%.

[0040] The polyoxyethylene ether emulsifier is a combination of aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and diphenylethyl phenol formaldehyde condensate polyoxyethylene ether.

[0041] The arylphenol polyoxyethylene ether is tristyrylphenol polyoxyethylene ether.

[0042] The fatty alcohol polyoxyethylene ether is isomeric tridecanol polyoxyethylene ether.

[0043] The mass ratio of the aromatic phenol polyoxyethylene ether, the fatty alcohol polyoxyethylene ether, the diphenylethylphenol formaldehyde condensate polyoxyethylene ether and the propylene glycol block polyether is 8:8:7:3.

[0044] The propylene glycol block polyether is a combination of L62 and L64, the mass ratio of L62 to L64 is 2:3, and the L62 and L64 are from Liaoning Kelong Fine Chemical Co., Ltd.

[0045] The solvent is a combination of dimethyl carbonate and dimethyl propionamide; the mass ratio of dimethyl carbonate to dimethyl propionamide is 1:1.

[0046] The cosolvent is cyclohexanone;

[0047] On the other hand, Example 1 of the present invention provides a method for preparing a microemulsion of pyraclostrobin and epoxiconazole:

[0048] (1) Add the cosolvent and solvent into the preparation kettle, turn on the stirrer, add pyraclostrobin and epoxiconazole, stir, dissolve and mix for 40 minutes;

[0049] (2) accurately weighing the polyoxyethylene ether emulsifier, the block polyether nonionic surfactant, and the defoamer according to the feeding ratio and sequentially adding them into the preparation kettle, turning on the stirrer to mix for 40 minutes;

[0050] (3) Add deionized water into the preparation kettle and mix for 60 minutes.

[0051] Example 2

[0052] Embodiment 2 of the present invention provides a pyraclostrobin and fluconazole microemulsion, which comprises, by weight percentage: 11.3% pyraclostrobin, 5.7% fluconazole, 28% polyoxyethylene ether emulsifier, 3% block polyether nonionic surfactant, 20% solvent, 5% cosolvent, 0.01% defoamer, and deionized water is supplemented to 100%.

[0053] The polyoxyethylene ether emulsifier is a combination of aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and diphenylethyl phenol formaldehyde condensate polyoxyethylene ether.

[0054] The arylphenol polyoxyethylene ether is tristyrylphenol polyoxyethylene ether.

[0055] The fatty alcohol polyoxyethylene ether is isomeric tridecanol polyoxyethylene ether.

[0056] The propylene glycol block polyether is a combination of L62 and L64, the mass ratio of L62 to L64 is 2:3, and the L62 and L64 are from Liaoning Kelong Fine Chemical Co., Ltd.

[0057] The mass ratio of the aromatic phenol polyoxyethylene ether, the fatty alcohol polyoxyethylene ether, the diphenylethylphenol formaldehyde condensate polyoxyethylene ether and the propylene glycol block polyether is 8:8:10:3.

[0058] The solvent is a combination of dimethyl carbonate and dimethyl propionamide; the mass ratio of dimethyl carbonate to dimethyl propionamide is 1:1.

[0059] The cosolvent is cyclohexanone;

[0060] Embodiment 2 of the present invention provides a method for preparing a microemulsion of pyraclostrobin and epoxiconazole on the other hand:

[0061] (1) Add the cosolvent and solvent into the preparation kettle, turn on the stirrer, add pyraclostrobin and epoxiconazole, stir, dissolve and mix for 40 minutes;

[0062] (2) accurately weighing the polyoxyethylene ether emulsifier, the block polyether nonionic surfactant, and the defoamer according to the feeding ratio and sequentially adding them into the preparation kettle, turning on the stirrer to mix for 40 minutes;

[0063] (3) Add deionized water into the preparation kettle and mix for 60 minutes.

[0064] Example 3

[0065] Embodiment 3 of the present invention provides a pyraclostrobin and fluconazole microemulsion, which comprises, by weight percentage: 12.75% pyraclostrobin, 4.25% fluconazole, 28% polyoxyethylene ether emulsifier, 3% block polyether nonionic surfactant, 20% solvent, 5% cosolvent, 0.01% defoamer, and deionized water is supplemented to 100%.

[0066] The polyoxyethylene ether emulsifier is a combination of aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and diphenylethyl phenol formaldehyde condensate polyoxyethylene ether.

[0067] The arylphenol polyoxyethylene ether is tristyrylphenol polyoxyethylene ether.

[0068] The fatty alcohol polyoxyethylene ether is isomeric tridecanol polyoxyethylene ether.

[0069] The propylene glycol block polyether is a combination of L62 and L64, the mass ratio of L62 to L64 is 2:3, and the L62 and L64 are from Liaoning Kelong Fine Chemical Co., Ltd.

[0070] The mass ratio of the aromatic phenol polyoxyethylene ether, the fatty alcohol polyoxyethylene ether, the diphenylethylphenol formaldehyde condensate polyoxyethylene ether and the propylene glycol block polyether is 8:8:10:3.

[0071] The solvent is a combination of dimethyl carbonate and dimethyl propionamide; the mass ratio of dimethyl carbonate to dimethyl propionamide is 1:1.

[0072] The cosolvent is cyclohexanone;

[0073] On the other hand, Example 3 of the present invention provides a method for preparing a microemulsion of pyraclostrobin and epoxiconazole:

[0074] (1) Add the cosolvent and solvent into the preparation kettle, turn on the stirrer, add pyraclostrobin and epoxiconazole, stir, dissolve and mix for 40 minutes;

[0075] (2) accurately weighing the polyoxyethylene ether emulsifier, the block polyether nonionic surfactant, and the defoamer according to the feeding ratio and sequentially adding them into the preparation kettle, turning on the stirrer to mix for 40 minutes;

[0076] (3) Add deionized water into the preparation kettle and mix for 60 minutes.

[0077] Comparative Example 1

[0078] Comparative Example 1 of the present invention is a commercially available 17% epoxiconazole suspoemulsion.

[0079] Comparative Example 2

[0080] Comparative Example 2 of the present invention provides a pyraclostrobin and fluopicolide microemulsion and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that, by weight percentage, it comprises: 12.3% pyraclostrobin, 4.7% fluopicolide, 22% polyoxyethylene ether emulsifier, 3% block polyether nonionic surfactant, 20% solvent, 0.01% defoamer, and deionized water is supplemented to 100%.

[0081] Comparative Example 3

[0082] Comparative Example 3 of the present invention provides a pyraclostrobin and fluconazole microemulsion and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that, by weight percentage, it comprises: 12.3% pyraclostrobin, 4.7% fluconazole, 22% polyoxyethylene ether emulsifier, 1% block polyether nonionic surfactant, 20% solvent, 5% cosolvent, 0.01% defoamer, and deionized water is supplemented to 100%, and the mass ratio of the aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, diphenylethyl phenol formaldehyde condensate polyoxyethylene ether, and propylene glycol block polyether is 10:10:2:1.

[0083] Comparative Example 4

[0084] Comparative Example 4 of the present invention provides a pyraclostrobin and epoxiconazole microemulsion and a preparation method thereof, and its specific implementation manner is the same as that of Example 1, except that the model of the propylene glycol block polyether is L31, which is sourced from Liaoning Kelong Fine Chemical Co., Ltd.

[0085] Comparative Example 5

[0086] Comparative Example 5 of the present invention provides a pyraclostrobin and fluopicolide microemulsion and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that, by weight percentage, it comprises: 12.3% of pyraclostrobin, 4.7% of fluopicolide, 22% of polyoxyethylene ether emulsifier, 3% of block polyether nonionic surfactant, 20% of solvent, 5% of cosolvent, 0.01% of defoamer, and deionized water is supplemented to 100%. The polyoxyethylene ether emulsifier is a combination of aromatic phenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether; the mass ratio of the aromatic phenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and propylene glycol block polyether is 11:11:3.

[0087] Performance Testing Methods

[0088] (1) According to O31 / 0116000265C039-2020 "17% pyraclostrobin·epiconazole microemulsion", and referring to GB / T1601-93 "Method for Determination of pH Value of Pesticide", GB / T28137-2011 "Method for Determination of Persistent Foaming Property of Pesticide", GB / T1603-2001 "Method for Determination of Emulsion Stability of Pesticide", GB / T19137-2003 "Method for Determination of Low Temperature Stability of Pesticide", and GB / T19136-2003 "Method for Determination of Thermal Storage Stability of Pesticide", the appearance, mass fraction of pyraclostrobin, mass fraction of epiconazole, pH value, emulsion stability, persistent foaming property, low temperature stability and thermal storage stability of the 17% pyraclostrobin·epiconazole microemulsion provided in Example 1 were tested. The test results all met the requirements of O31 / 0116000265C039-2020. The results are shown in Figure 1 .

[0089] (2) According to the standards of NY / T1156.2-2006 and NY / T1156.6-2006, the toxicity of pyraclostrobin and epoxiconazole and their mixtures in the ratios of 1:1, 2:1, 3:1, 4:1 and 5:1 against the corn leaf blight pathogen was determined by the drug-containing culture medium method. The results showed that the mixtures of pyraclostrobin and epoxiconazole in the above five ratios showed a synergistic effect against the corn leaf blight pathogen, with EC50 values ​​of 1.38 mg / L, 1.44 mg / L, 1.56 mg / L, 1.80 mg / L and 2.08 mg / L, respectively, and co-toxicity coefficients of 131.78, 149.02, 151.04, 139.36 and 125.68, respectively. The synergistic effect of the mixtures of the two in the ratios of 2:1 and 3:1 was more obvious. The results are shown in Figure 2 .

[0090] (3) The 17% oxathiapiprolin-epiconazole microemulsion prepared in Example was used in a field efficacy test for controlling wheat fusarium head blight. The method and results are shown in Figure 3 .

[0091] (4) The 17% oxathiapiprolin-epiconazole microemulsion prepared in Example was used in a field efficacy test for the prevention and treatment of corn leaf blight. The method and results are shown in Figure 4 .

[0092] (5) The surface tension of Example 1 and Comparative Example 1 was measured after diluting them 2000 times with water. The results are shown in Figure 5 .

[0093] (6) Referring to GB / T19137-2003 “Method for Determining Low Temperature Stability of Pesticides”, the low temperature stability of the pyraclostrobin and epoxiconazole microemulsions obtained in Example 1 and Comparative Example 2 of the present invention was determined. The results are shown in Figure 6 , Comparative Example 2 had a crystal precipitation problem during 7 days cold storage at 0°C ( Figure 6 a), while Example 1 remained homogeneous, clear and transparent after being stored at -6°C for 30 days, without crystal precipitation ( Figure 6 b).

[0094] (7) Referring to the method for determining the thermal storage stability of pesticides in GB / T 19136-2003, the low temperature stability of the pyraclostrobin and epoxiconazole microemulsions obtained in Example 1 and Comparative Example 3 was determined. The results are shown in Figure 6 , after 14 days of hot storage at 54°C, the sample of Comparative Example 3 showed stratification problem ( Figure 7 a), while Example 1 passed the 14-day hot storage test at 54°C without stratification ( Figure 7 b).

[0095] (8) The pyraclostrobin and epoxiconazole microemulsions obtained in Example 1 and Comparative Example 4 were diluted 200 times with water. Figure 8 , Comparative Example 4 was diluted 200 times with water and became milky white ( Figure 8 a), while Example 1 was transparent and had blue fluorescence after being diluted 200 times with water ( Figure 8 b).

[0096] (9) The pyraclostrobin and epoxiconazole microemulsions obtained in Example 1 and Comparative Example 5 of the present invention were mixed with a 20-fold dilution of potassium dihydrogen phosphate. The results are shown in Table 1. Fig. 9 , after mixing with 20 times diluted potassium dihydrogen phosphate, comparative example 5 could not maintain homogeneous and stable dispersion, and flocculation occurred ( Fig. 9 a), while Example 1 remained homogeneously dispersed after being mixed with a 20-fold dilution of potassium dihydrogen phosphate, and no flocculation occurred ( Fig. 9 b).

Claims

1. A pyraclostrobin and epoxiconazole microemulsion, characterized in that: The invention comprises, by weight percentage, 2-15% of pyraclostrobin, 1-6% of epoxiconazole, 8%-30% of a polyoxyethylene ether emulsifier, 1-5% of a block polyether nonionic surfactant, 15-45% of a solvent, 3-15% of a cosolvent, 0.005-0.05% of a defoamer and deionized water to make up to 100%; the mass ratio of pyraclostrobin to epoxiconazole is (2-3):1; the polyoxyethylene ether emulsifier is a combination of tristyrylphenol polyoxyethylene ether, isomeric tridecanol polyoxyethylene ether and diphenylethylphenol formaldehyde condensate polyoxyethylene ether; the block polyether nonionic surfactant is The ionic surfactant is propylene glycol block polyether, and the propylene glycol block polyether is a combination of L62 and L64; the mass ratio of L62 and L64 is (1-2): (1.5-3); the mass ratio of tristyrylphenol polyoxyethylene ether, isomeric tridecanol polyoxyethylene ether, diphenylethylphenol formaldehyde condensate polyoxyethylene ether, and propylene glycol block polyether is (6-10): (7-9): (5-10): (2-5); the solvent is a combination of dimethyl carbonate and dimethyl propionamide; the mass ratio of dimethyl carbonate and dimethyl propionamide is (0.8-1.2):

1.

2. A method for preparing the microemulsion of pyraclostrobin and epoxiconazole according to claim 1, characterized in that: At least the following steps are included: (1) Add the cosolvent and solvent into the preparation kettle, turn on the stirrer, add pyraclostrobin and epoxiconazole, stir, dissolve and mix for 30-60 minutes; (2) accurately weigh the polyoxyethylene ether emulsifier, block polyether nonionic surfactant, and defoamer according to the feed ratio and add them into the preparation kettle in sequence, turn on the stirrer and mix for 30-60 minutes; (3) Add deionized water into the preparation kettle and mix for 30-60 minutes.

3. A use of the pyraclostrobin and epoxiconazole microemulsion according to claim 1, characterized in that: Used for the prevention and control of corn leaf blight, wheat powdery mildew and ergot.

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