An aqueous emulsion containing acetamiprid and lambda-cyhalothrin and a preparation method thereof

Abstract

The present invention discloses an aqueous emulsion containing acetamiprid and lambda-cyhalothrin and a preparation method thereof. The aqueous emulsion is composed of the following components in parts by weight: 10-100 g / L of active ingredient, 60-120 g / L of emulsifier, 100-200 g / L of solvent, 50-150 g / L of cosolvent, 1-10 g / L of thickener, 0.5-2 g / L of defoamer, 3-10 g / L of antifreeze, 1-2 g / L of pH regulator, 1-2 g / L of preservative, and the balance of water; wherein, the mass ratio of acetamiprid to lambda-cyhalothrin is 1-20:1. The aqueous emulsion of the present invention has strong stability over time, can withstand the high and low temperature range of 0°C to 54°C, effectively reduces or solves the influence of environmental changes during transportation on the stability of the dosage form, reduces or avoids product quality problems such as stratification or sedimentation, flocculation, coalescence, crystal precipitation, decomposition, etc. of the dosage form, improves the stability of the preparation, and improves the insecticidal effect.

Description

Technical Field

[0001] The present invention relates to a pesticide aqueous emulsion, specifically to an aqueous emulsion containing acetamiprid and lambda-cyhalothrin and a preparation method thereof, belonging to the technical field of pesticide formulations. Background Art

[0002] Acetamiprid (chemical name: N-(N-cyano-ethanimino)-N-methyl-2-chloropyridine-5-methanamine) belongs to nitro-substituted methylene heterocyclic compounds. It is a new broad-spectrum insecticide with certain acaricidal activity and is highly effective against pests resistant to organophosphates, carbamates, and pyrethroids. The technical material is a white crystal, with a melting point of 101.0 - 103.3°C and a vapor pressure > 1.33×10-6 Pa (25°C). Its solubility in water at 25°C is 4200 mg / L, and it can dissolve in acetone, methanol, ethanol, dichloromethane, chloroform, acetonitrile, tetrahydrofuran, etc. It is stable in water at pH = 7, and gradually hydrolyzes at 45°C when pH = 9, and is stable under sunlight. Currently, the main formulated products are emulsifiable concentrates, aqueous emulsions, wettable powders, and water-dispersible granules.

[0003] Lambda-cyhalothrin (chemical name: α-cyano-3-phenoxybenzyl 3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropanecarboxylate) is a pyrethroid insecticide and acaricide, mainly acting by contact and stomach poisoning, without systemic action. It has good effects on various pests such as Lepidoptera, Coleoptera, and Hemiptera, as well as other pests, and also on spider mites, rust mites, gall mites, tarsonemid mites, etc. It can also be used to control various surface and public health pests, and has a certain control effect on piercing-sucking mouthpart pests, but long-term use is likely to cause resistance to them. The pure product is a white solid, and the industrial product is a light yellow solid, with a melting point of 49.2°C and a vapor pressure of 200×10-9 Pa (2.67×10-7 Pa) (20°C). The boiling point is 187 - 190°C, and it is easily soluble in various organic solvents such as acetone, methanol, ethyl acetate, toluene, etc., with a solubility > 500 g / L; it is insoluble in water. It can be stably stored for more than half a year at normal temperature; its half-life in water under sunlight is 20 d; its half-life in soil is 22 - 82 d. Currently, the main formulated products are emulsifiable concentrates, aqueous emulsions, and microcapsule suspensions.

[0004] The long-term and large-scale use of a single pesticide can easily cause pests to develop drug resistance, leading to an increase in the dosage of pesticides, a decrease in the control effect, and a shortening of the effective period, which is not conducive to the sustainable development of the environment. One of the commonly used methods to delay the emergence of pest drug resistance is to compound active ingredients with different mechanisms of action. Acetamiprid and lambda-cyhalothrin have different mechanisms of action, and the research on the compound preparation of acetamiprid and lambda-cyhalothrin will have good application prospects. Patents such as CN104430485A and CN 104351239A have proven the synergistic effect of the compound preparation containing acetamiprid and lambda-cyhalothrin.

[0005] At present, in the pesticide formulation structure of our country, old formulations such as emulsifiable concentrates and wettable powders still occupy a large share. Emulsifiable concentrates contain a large amount of organic solvents such as toluene, xylene, and methanol. These organic solvents will cause harm to the human body during the processing, packaging, and use of emulsifiable concentrates, reducing the quality of agricultural products, affecting the export earnings of agricultural products, and polluting the soil, water sources, etc. In developed countries, the use of emulsifiable concentrates on vegetables and fruit trees is strongly resisted. The flash point of organic solvents is relatively low, belonging to flammable and explosive items, making the safety of emulsifiable concentrate preparations poor, inconvenient for processing, packaging, storage, and transportation, especially causing waste of organic solvents. In recent years, with the continuous soaring of world fuel prices, the prices of organic solvents such as toluene and xylene have been rising all the way, resulting in a substantial increase in the manufacturing cost of emulsifiable concentrates.

[0006] The dust generated during the processing and use of powders and wettable powders also poses a potential hazard to human health. Therefore, the development of water-based preparations with strong safety, environmental friendliness, and low price has become an international trend. Emulsion in water replaces a large amount of organic solvents with water and only contains a small amount of organic solvents, which can greatly reduce environmental pollution. It belongs to a new type of environmentally friendly pesticide preparation and avoids many environmental problems caused by organic solvents. Water-based preparations are a type of pesticide processing formulation with water as the medium or diluent. This type of formulation has the characteristics of low phytotoxicity, low toxicity, easy dilution, non-flammable, non-explosive, easy to use, easy to measure, and beneficial to environmental protection. At present, there is no report on the compound emulsion in water of acetamiprid and lambda-cyhalothrin.

[0007] An emulsion in water is an emulsion in which tiny droplets obtained by mixing a pesticide technical with a solvent are dispersed in water. It is a thermodynamically unstable system and is very likely to have problems such as stratification or sedimentation, flocculation, coalescence, crystal precipitation, or phase inversion. Pesticides with high water solubility have a great impact on the stability of the emulsion, and it is very difficult to process them into an emulsion in water. Generally speaking, the water solubility of the active ingredient of the pesticide used for processing an emulsion in water is expected to be below 1000 mg / L. However, the water solubility of acetamiprid is 4200 mg / L, far exceeding this limit condition. Therefore, it is very difficult to compound and process acetamiprid and lambda-cyhalothrin into a stable emulsion in water.

[0008] A pesticidal composition of imidacloprid and acetamiprid aqueous emulsion is disclosed in CN101836657 A. However, no description is made on the cold storage stability of the aqueous emulsion. The obtained aqueous emulsion is not resistant to low temperature, and problems such as stratification and sedimentation, coalescence, and crystal precipitation will occur within a short time in a low-temperature environment, which is not conducive to production and storage in a low-temperature environment and also limits the use areas and shelf life of the product.

[0009] In summary, at present, preparing a stable compound aqueous emulsion of acetamiprid and lambda-cyhalothrin is still a difficult problem for formulation engineers. Therefore, it is still of great significance to develop an aqueous emulsion that can maintain stability during storage. Summary of the Invention

[0010] Due to the high water solubility of acetamiprid, it is difficult to ensure excellent stability over time. Therefore, the existing compound formulations of acetamiprid and lambda-cyhalothrin on the market are emulsifiable concentrate formulations and water dispersible granules, and it is very difficult to develop them into aqueous emulsions. The aqueous emulsion uses water to replace a large amount of organic solvents and only contains a small amount of organic solvents, which can greatly reduce environmental pollution and belongs to a new type of environmentally friendly pesticide formulation. Therefore, developing the two into an aqueous emulsion has good economic benefits. In addition, since different technical materials require selecting solvents that can dissolve the technical materials and suitable emulsifiers to prepare an aqueous emulsion with good stability, and the currently available solvents are relatively few, the research and development of the aqueous emulsion of acetamiprid and lambda-cyhalothrin is relatively difficult at present.

[0011] To solve the problems existing in the preparation of the aqueous emulsion of acetamiprid and lambda-cyhalothrin, the inventor has carried out a large amount of screening work on the formulation system and finally obtained the best-matched auxiliary agent system, thereby obtaining an aqueous emulsion preparation with excellent performance. The aqueous emulsion containing acetamiprid and lambda-cyhalothrin of the present invention includes active ingredients and auxiliary agents. The auxiliary agents are solvents, cosolvents, emulsifiers, thickeners, defoamers, antifreezing agents, pH regulators, preservatives, and water. The active ingredients are composed of acetamiprid and lambda-cyhalothrin. In the active ingredients, the mass ratio of acetamiprid to lambda-cyhalothrin is (1-20):1.

[0012] Through the synergistic cooperation of each auxiliary agent, especially the screening and combination of solvents, cosolvents, emulsifiers, and thickeners, the stability of the dosage form is greatly improved. The obtained product has strong stability over time, can withstand the high and low temperature range of 0°C to 54°C, effectively reduces or solves the influence of environmental changes during transportation on the stability of the dosage form, reduces or avoids product quality problems such as stratification or sedimentation, flocculation, coalescence, crystal precipitation, and decomposition of the dosage form, improves the stability of the preparation, and improves the insecticidal effect.

[0013] Furthermore, the solvent is one or more of methyl oleate, dimethyl carbonate, sec-butyl acetate, and solvent naphtha No. 200, and preferably solvent naphtha No. 200.

[0014] Furthermore, the cosolvent is one or more of ethanol, acetone, N-methylpyrrolidone, isophorone, and cyclohexanone, preferably N-methylpyrrolidone.

[0015] Furthermore, the emulsifier is one or more of alkylphenol polyoxyethylene ether, phenethylphenol polyoxyethylene polyoxypropylene ether, calcium dodecylbenzenesulfonate, castor oil polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and propylene oxide-ethylene oxide block polyether, preferably a mixture of castor oil polyoxyethylene ether and propylene oxide-ethylene oxide block polyether with a mass ratio of 1-3:1.

[0016] Furthermore, the thickener is at least one of aluminum magnesium silicate, methylcellulose, hydroxyethylcellulose, and xanthan gum, preferably a mixture of aluminum magnesium silicate and xanthan gum with a mass ratio of 1-3:1.

[0017] Furthermore, the defoamer is at least one of polyether defoamer, silicone defoamer, and polyether modified polysiloxane defoamer, preferably silicone defoamer.

[0018] Furthermore, the antifreeze is at least one of urea, ethylene glycol, propylene glycol, glycerol, polyethylene glycol, and sodium chloride, preferably ethylene glycol.

[0019] Furthermore, the pH regulator is at least one of citric acid and acetic acid, preferably citric acid.

[0020] Furthermore, the preservative is at least one of Kathon, paraformaldehyde, and sodium benzoate, preferably Kathon.

[0021] Furthermore, in the above-mentioned aqueous emulsion, the content of the active ingredient is 10-100 g / L, such as 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L.

[0022] Furthermore, in the above-mentioned aqueous emulsion, the content of the solvent is 100-200 g / L, such as 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 150 g / L, 160 g / L, 170 g / L, 180 g / L, 190 g / L, 200 g / L, preferably 190-200 g / L.

[0023] Furthermore, in the above-mentioned aqueous emulsion, the content of the cosolvent is 50-150 g / L, such as 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 150 g / L, preferably 100-110 g / L.

[0024] Further, in the above-mentioned aqueous emulsion, the content of the emulsifier is 60 - 120 g / L, such as 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 110 g / L, 120 g / L.

[0025] Further, in the above-mentioned aqueous emulsion, the content of the thickener is 1 - 10 g / L, such as 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, and preferably 4 - 6 g / L.

[0026] Further, in the above-mentioned aqueous emulsion, the content of the defoamer is 0.5 - 2 g / L, such as 0.5 g / L, 0.7 g / L, 0.9 g / L, 1 g / L, 1.2 g / L, 1.4 g / L, 1.6 g / L, 1.8 g / L, 2 g / L, and preferably 1 - 2 g / L.

[0027] Further, in the above-mentioned aqueous emulsion, the content of the antifreeze is 3 - 10 g / L, such as 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, and preferably 5 - 6 g / L.

[0028] Further, in the above-mentioned aqueous emulsion, the content of the pH regulator is 1 - 2 g / L, such as 1 g / L, 1.1 g / L, 1.2 g / L, 1.3 g / L, 1.4 g / L, 1.5 g / L, 1.6 g / L, 1.7 g / L, 1.8 g / L, 1.9 g / L, 2 g / L.

[0029] Further, in the above-mentioned aqueous emulsion, the content of the preservative is 1 - 2 g / L, such as 1 g / L, 1.1 g / L, 1.2 g / L, 1.3 g / L, 1.4 g / L, 1.5 g / L, 1.6 g / L, 1.7 g / L, 1.8 g / L, 1.9 g / L, 2 g / L.

[0030] Further, in the above-mentioned aqueous emulsion, the amount of water is used to make up the balance to ensure that the contents of the above components are within the specified range.

[0031] The present invention also provides a preparation method of the above-mentioned aqueous emulsion containing acetamiprid and lambda-cyhalothrin, and the method includes the following steps: mixing acetamiprid, lambda-cyhalothrin, a solvent, a cosolvent and an emulsifier to form a homogeneous and transparent oil phase; stirring and mixing water, a thickener, an antifreeze, a defoamer, a pH regulator and a preservative to form a homogeneous aqueous phase; pouring the oil phase into the aqueous phase under high-speed shearing to obtain an aqueous emulsion with an average particle size of less than 5 μm.

[0032] Furthermore, acetamiprid, highly effective chlorfenapyr, solvent, co-solvent and emulsifier can be mixed at 40-50° C. to accelerate the dissolution rate.

[0033] Furthermore, the speed of high-speed shearing is generally 8000-10000 r / min, and the shearing time is 10-30 minutes.

[0034] The present invention has the following beneficial effects:

[0035] 1. The present invention screens the auxiliary agent system, and obtains a stable acetamiprid and high-efficiency chlorflucythrinate composite aqueous emulsion by matching various auxiliary agents, especially solvents, cosolvents, emulsifiers and thickeners. While ensuring the stability of the product over time, it reduces or avoids the problems of stratification or sedimentation, flocculation, aggregation, crystal precipitation, decomposition, etc. of the aqueous emulsion, thereby improving the stability of the preparation.

[0036] 2. The aqueous emulsion of the present invention has good emulsification and dispersibility, a certain viscosity, is easier to adhere to the surface of pests, and can withstand high and low temperature ranges of 0°C to 54°C. It is not easily affected by environmental changes during sea transportation. When the environment undergoes temperature changes, its physical stability remains high, thereby ensuring the insecticidal effect.

[0037] 3. The aqueous emulsion provided by the present invention provides a good idea for solving the stability problem of the aqueous emulsion of high-solubility and low-melting-point pesticides. The present invention will play a certain role in promoting the development of pesticide formulations in my country and will also bring good economic benefits to enterprises.

[0038] 4. The aqueous emulsion of the present invention can realize the compounding of acetamiprid and high-efficiency chlorflucythrinate, thereby improving the insecticide effect, reducing the dosage of the agent, and reducing the agent cost. DETAILED DESCRIPTION

[0039] The technical content of the present invention is further explained below through specific embodiments, but the essential content of the present invention is not limited to the following embodiments.

[0040] Example 1

[0041] A water emulsion, the formula is shown in Table 1, the content of each component is: active ingredient 20g / L, solvent No. 200 solvent oil 200g / L, cosolvent N-methyl pyrrolidone 100g / L, emulsifier castor oil polyoxyethylene ether 30g / L, propylene oxide-ethylene oxide block polyether 30g / L, thickener magnesium aluminum silicate 4.5g / L, xanthan gum 1.5g / L, antifreeze agent ethylene glycol 5g / L, defoamer silicone defoamer 1g / L, pH adjuster citric acid 1.5g / L, preservative kason 1g / L, water balance. Among them, the active ingredients are acetamiprid and high-efficiency chlorflucythrin in a mass ratio of 1:1.

[0042] The preparation method of the above-mentioned emulsion in water is as follows: acetamiprid and lambda-cyhalothrin are dissolved using a solvent, a co-solvent and an emulsifier to form a homogeneous and transparent oil phase; water, a thickening agent, an antifreezing agent, an antifoaming agent, a pH regulator and a preservative are stirred and mixed to form a homogeneous water phase; the oil phase is poured into the water phase under high-speed shearing for 10 - 30 minutes, and the shearing speed is 8000 - 10000 r / min to obtain an emulsion in water with an average particle size of less than 5 μm.

[0043] Examples 2 - 14 and Comparative Example 1

[0044] A series of emulsions in water are prepared according to the formulations in Table 1, and the preparation method of each emulsion in water refers to Example 1.

[0045] Table 1 Formulations of Emulsions in Water

[0046]

[0047]

[0048] The quality stability of the emulsions in water prepared in the above examples and comparative examples is detected, and the results are shown in Table 2 below.

[0049] Table 2 Product Properties of Emulsions in Water Prepared by the Compound of Acetamiprid and Lambda-cyhalothrin

[0050]

[0051] As can be seen from Table 2, Examples 1 - 8 have the best effects, and there is no water separation, oil floating or precipitation before and after hot and cold storage. Examples 9 - 14 have better effects, and their performance is slightly worse than that of the preferred Examples 1 - 8, but it does not affect the use effect, and there is only a small amount of precipitation before and after hot and cold storage. The comparative example does not select the solvents and additives of the present invention, and its performance is very poor, and it cannot ensure the chronological stability of the product. It can be seen from this that the selection and dosage of additives play a key role in the product quality.

Claims

1. An aqueous emulsion containing acetamiprid and lambda-cyhalothrin, characterized in that it is composed of the following components in parts by weight: active ingredient 10 - 100 g / L, emulsifier 60 - 120 g / L, solvent 100 - 200 g / L, cosolvent 50 - 150 g / L, thickener 1 - 10 g / L, defoamer 0.5 - 2 g / L, antifreeze 3 - 10 g / L, pH regulator 1 - 2 g / L, preservative 1 - 2 g / L, and water in the balance; wherein, the mass ratio of acetamiprid to lambda-cyhalothrin is 1~20:1; the solvent is No. 200 solvent oil; the cosolvent is N-methylpyrrolidone; the emulsifier is a mixture of castor oil polyoxyethylene ether and propylene oxide-ethylene oxide block polyether with a mass ratio of 1 - 3:1; the thickener is a mixture of magnesium aluminum silicate and xanthan gum with a mass ratio of 1 - 3:1; the defoamer is an organosilicon defoamer; the antifreeze is ethylene glycol; the pH regulator is citric acid; the preservative is Kathon.

2. The aqueous emulsion according to claim 1, characterized in that: it is composed of the following components in parts by weight: active ingredient 10 - 100 g / L, emulsifier 60 - 120 g / L, solvent 190 - 200 g / L, cosolvent 100 - 110 g / L, thickener 4 - 6 g / L, defoamer 1 - 2 g / L, antifreeze 5 - 6 g / L, pH regulator 1 - 2 g / L, preservative 1 - 2 g / L, and water in the balance.

3. A preparation method of the aqueous emulsion containing acetamiprid and lambda-cyhalothrin according to claim 1 or 2, characterized in that it includes the following steps: Mix acetamiprid, lambda-cyhalothrin, solvent, cosolvent and emulsifier to form a homogeneous and transparent oil phase; Stir and mix water, thickener, antifreeze, defoamer, pH regulator and preservative to form a homogeneous water phase; Pour the oil phase into the water phase under high-speed shearing to obtain an aqueous emulsion with an average particle size of less than 5 µm.

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