Plant essential oil compounded insecticidal missible oil agent and preparation method thereof

Abstract

The invention belongs to the technical field of pesticide preparations, and particularly relates to a plant essential oil compounded insecticidal missible oil agent and a preparation method thereof. The peppermint essential oil and the cinnamon essential oil are processed to form a plant essential oil compound, the plant essential oil compound is combined with other functional components including the sulfonated polyethylene glycol and the chitosan modified carboxymethyl cellulose for common use, the plant essential oil compounded insecticidal missible oil agent is prepared, and by means of the synergistic effect of the multiple components, the synergistic effect is achieved; good heat storage stability and low-temperature stability of the insecticidal emulsifiable concentrate are ensured, and meanwhile, the insecticidal efficacy is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticide preparations, and particularly relates to an insecticide emulsifiable concentrate compounded with plant essential oils and a preparation method thereof. Background Art

[0002] Insecticidal emulsifiable concentrate is a pesticide formulation, usually a mixture of one or more insecticide effective ingredients (active ingredients) with auxiliary ingredients such as solvents and emulsifiers. This formulation is diluted into an aqueous solution when used and then sprayed on plants to control pests. The characteristic of emulsifiable concentrate is that its main ingredients can be dissolved in organic solvents to form a uniform liquid state. When added to water, it can be dispersed into fine oil droplets under the action of emulsifiers to form a stable emulsion. This form allows the agent to better adhere to the surface of the plant and helps the active ingredients penetrate into the body of the pest, improving the insecticidal effect.

[0003] A Chinese patent (publication number CN116649360A) discloses an insecticide emulsifiable concentrate formulation for controlling agricultural pests, its preparation method and application. The invention obtains a stable production formula of cypermethrin·probromophos emulsifiable concentrate by screening a suitable mixed solvent and stabilizer system and controlling the pH range of the product, solving the problem of excessively high decomposition rate of probromophos in cypermethrin·probromophos emulsifiable concentrate products. The decomposition rate of the active ingredients cypermethrin and probromophos can be controlled to be less than 5% after 2 years of storage at room temperature, which is beneficial to the storage of the product during the shelf life of the commodity, reduces the cost of the enterprise, and lays a solid foundation for the industrialized stable production of cypermethrin·probromophos emulsifiable concentrate products. However, the patent does not solve the problems of poor thermal storage stability and low temperature stability of insecticide emulsifiable concentrates in the prior art, and the insecticide efficacy needs to be improved, which seriously affects its practical application.

[0004] Therefore, how to add plant essential oils to insecticide emulsions, ensure the good thermal storage stability and low-temperature stability of insecticide emulsions through the compound use of plant essential oils and combined with other functional components, while improving the insecticide efficacy has become a direction that needs to be focused on. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide an insecticide emulsifiable concentrate compounded with plant essential oils and a preparation method thereof, aiming to solve the problems of poor thermal storage stability and low-temperature stability of insecticide emulsifiable concentrates in the prior art, and the need to improve the insecticide efficacy.

[0006] The present invention processes peppermint essential oil and cinnamon essential oil to form a plant essential oil composite, and uses other functional components, such as sulfonated polyethylene glycol and chitosan-modified carboxymethyl cellulose, to prepare an insecticide emulsifiable concentrate compounded with plant essential oils. With the synergistic effect of multiple components, the insecticide emulsifiable concentrate has good heat storage stability and low-temperature stability, and the insecticide efficacy is improved.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows: The first aspect of the present invention provides a method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils, comprising the following steps: Step S1: In parts by weight, 1-3 parts of sodium alginate and 80-100 parts of deionized water are uniformly stirred to obtain a sodium alginate aqueous solution; 2-4 parts of peppermint essential oil and 80-100 parts of anhydrous ethanol are mixed, and then 80-100 parts of the sodium alginate aqueous solution are added for ultrasonic dispersion to obtain a peppermint essential oil mixed solution; Step S2: 10-20 parts of anhydrous ethanol and 80-100 parts of deionized water are mixed, and then 2-4 parts of microcrystalline cellulose are added and stirred evenly, and then 2-6 parts of cinnamon essential oil, 0.6-0.8 parts of Tween 80, 1-3 parts of glycerol and 1-3 parts of calcium chloride are added and high-speed homogenized to obtain a cinnamon essential oil mixed solution; Step S3: coaxially electrospinning the peppermint essential oil mixture and the cinnamon essential oil mixture to obtain a plant essential oil compound; Step S4: 50-60 parts of ethyl acetate, 2-4 parts of stabilizer, 16-20 parts of cypermethrin and 20-30 parts of bromophos are stirred evenly, 10-20 parts of emulsifier, 8-12 parts of plant essential oil compound, 6-10 parts of sulfonated polyethylene glycol and 4-8 parts of chitosan-modified carboxymethyl cellulose are added and mixed evenly, and finally 0.4-0.8 parts of pH regulator are added to obtain an insecticide emulsifiable concentrate compounded with plant essential oil; The preparation method of the sulfonated polyethylene glycol comprises: adding 6 to 8 parts of polyethylene glycol to 200 to 220 parts of deionized water, stirring and dissolving, then adding 4 to 6 parts of sodium vinyl sulfonate, 1 to 3 parts of acrylic acid and 0.6 to 0.8 parts of ammonium persulfate for heating reaction, and freeze drying to obtain the sulfonated polyethylene glycol; The preparation method of chitosan-modified carboxymethyl cellulose comprises: adding 1-3 parts of chitosan to 100-120 parts of anhydrous ethanol to obtain liquid A, adding 6-8 parts of potassium hydroxide to 100-120 parts of deionized water to fully dissolve, adding 2-6 parts of carboxymethyl cellulose and 100-120 parts of the liquid A to stir and obtain chitosan-modified carboxymethyl cellulose.

[0008] As a preferred technical solution of the present invention, the microcrystalline cellulose is modified microcrystalline cellulose; the preparation method of the modified microcrystalline cellulose comprises: adding 4 to 8 parts of microcrystalline cellulose to 80 to 100 parts of deionized water by weight for ultrasonic dispersion for 1 to 3 hours, then adding 40 to 50 parts of L-malic acid for reaction at 90 to 96° C. for 10 to 12 hours, adding 0.2 to 0.4 parts of silane coupling agent KH-550 for ultrasonic dispersion for 2 to 4 hours after the reaction is completed, filtering, washing with water, and drying to obtain modified microcrystalline cellulose.

[0009] Alginate in the peppermint essential oil mixture can be used as an emulsifier stabilizer to prevent the separation of the oil and water phases, and slow down the merging speed of oil droplets by forming a protective film on the surface, thereby improving the physical stability of the insecticide emulsion; in addition, the protective film can also block oxygen, moisture and other factors that may cause oxidation or chemical reactions, thereby improving the thermal storage stability of the product; the cinnamon essential oil mixture introduces modified microcrystalline cellulose through the cinnamon essential oil mixture, and the modified microcrystalline cellulose can significantly increase the viscosity of the emulsion, prevent the separation of the oil phase and the water phase at low temperatures, reduce the movement and merging of oil droplets through a high-viscosity system, maintain the uniformity of the emulsion, avoid stratification or precipitation, and thus ensure the low-temperature stability of the insecticide emulsion.

[0010] As a preferred technical solution of the present invention, the conditions for the high-speed homogenization treatment in step S2 include: stirring and mixing for 1 to 3 minutes at a speed of 6000 to 8000 r / min using a high-speed shear homogenizer, and then performing vacuum defoaming.

[0011] As a preferred technical solution of the present invention, the conditions for the heating reaction include: under a nitrogen atmosphere, a temperature of 80-90° C., and a time of 60-80 min.

[0012] The sulfonic acid group of sulfonated polyethylene glycol has good hydrophilicity and ionic properties, and can form a stronger interaction with the wax layer on the surface of plants, which helps the emulsifiable concentrate to better adhere to plant leaves and promotes the penetration of insecticide ingredients through the plant epidermis or the body surface of insects.

[0013] As a preferred technical solution of the present invention, the stirring treatment conditions include: stirring at 400-500 r / min for 6-8 hours, washing with anhydrous ethanol after stirring, and drying.

[0014] As a preferred technical solution of the present invention, the viscosity of the carboxymethyl cellulose is 500-1000 Pa.s.

[0015] The chitosan in chitosan-modified carboxymethyl cellulose has good film-forming and adhesion properties, and can form strong interactions with anionic components on the plant surface (such as fatty acids in the wax layer). Carboxymethyl cellulose is an anionic polysaccharide that can form a stable colloidal structure. The two can form a composite structure through electrostatic attraction and hydrogen bonding to enhance the adhesion and permeability of the emulsion on the plant surface, and promote the penetration of active ingredients through the plant epidermis or the insect body surface, thereby improving the insecticide efficacy.

[0016] As a preferred technical solution of the present invention, the conditions for the coaxial electrospinning are: the peppermint essential oil mixture is used as the core layer spinning solution, the cinnamon essential oil mixture is used as the shell layer spinning solution, the syringe propulsion speed of the shell layer spinning solution is 0.5~1.0ml / h, the syringe propulsion speed of the core layer spinning solution is 0.1~0.3ml / h, the needle voltage is 18~22kv, the receiving distance is 16~18cm, the temperature is 30~40℃, the humidity is 35~45%, the spinning time is 1~2h, and freeze-drying is performed after spinning is completed.

[0017] As a preferred technical solution of the present invention, the emulsifier is calcium dodecylbenzene sulfonate and castor oil polyoxyethylene ether; the mass ratio of calcium dodecylbenzene sulfonate and castor oil polyoxyethylene ether is (1~2):1.

[0018] The present invention selects calcium dodecylbenzene sulfonate and castor oil polyoxyethylene ether as emulsifiers and controls the mass ratio of the two to ensure a good compounding effect, so that the insecticide emulsifiable concentrate compounded with plant essential oils has a lower surface tension, is conducive to the adhesion of the insecticide emulsifiable concentrate to the target, is not prone to rebound, and has a better spreading effect so that the final attachment area is larger, thereby ensuring good thermal storage stability and low-temperature stability of the insecticide emulsifiable concentrate and improving the insecticide efficacy.

[0019] As a preferred technical solution of the present invention, the stabilizer is selected from any one or a combination of at least two of epoxy soybean oil, epichlorohydrin, and triphenyl phosphate; As a preferred technical solution of the present invention, the pH regulator is selected from any one of ethanolamine, triethanolamine and diisopropylamine, or a combination of at least two thereof.

[0020] The second aspect of the present invention provides an insecticide emulsifiable concentrate compounded with plant essential oils prepared by the method described in the first aspect.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The peppermint essential oil mixture of the present invention contains sodium alginate, and the cinnamon essential oil mixture introduces calcium ions through calcium chloride. In the process of electrospinning to form a plant essential oil compound, sodium alginate encounters calcium ions to form a stable gel structure. With the help of the gel structure, the plant essential oil can be effectively sustained-released, and the insecticide emulsifiable concentrate can be used in conjunction with profenofos and cypermethrin to ensure the sustained efficacy of the insecticide emulsifiable concentrate. At the same time, alginate can also be complexed with the sulfonic acid group of sulfonated polyethylene glycol and the amino group in chitosan-modified carboxymethyl cellulose to form a protective layer to avoid the influence of the harsh external environment, thereby improving the thermal storage stability and low-temperature stability of the insecticide emulsifiable concentrate.

[0022] (2) The alginate in the peppermint essential oil mixture of the present invention can be used as an emulsifier stabilizer to prevent the separation of the oil-water phase. By forming a protective film on the surface, the merging speed of the oil droplets is slowed down, thereby improving the physical stability of the insecticide emulsion. In addition, the protective film can also block oxygen, moisture and other factors that may cause oxidation or chemical reactions, thereby improving the thermal storage stability of the product. The cinnamon essential oil mixture introduces modified microcrystalline cellulose through the cinnamon essential oil mixture. The modified microcrystalline cellulose can significantly increase the viscosity of the emulsion, prevent the separation of the oil phase and the water phase at low temperatures, reduce the movement and merging of the oil droplets through the high viscosity system, maintain the uniformity of the emulsion, avoid stratification or precipitation, thereby ensuring the low-temperature stability of the insecticide emulsion.

[0023] (3) The sulfonic acid group of the sulfonated polyethylene glycol of the present invention has good hydrophilicity and ionic properties, and can form a stronger interaction with the wax layer on the surface of the plant, which helps the emulsifiable concentrate to better adhere to the plant leaves and promotes the penetration of the insecticide components through the plant epidermis or the insect body surface.

[0024] (4) The chitosan in the chitosan-modified carboxymethyl cellulose of the present invention has good film-forming and adhesion properties, and can form a strong interaction with the anionic components on the plant surface (such as fatty acids in the wax layer), while carboxymethyl cellulose is an anionic polysaccharide that can form a stable colloidal structure. The two can form a composite structure through electrostatic attraction and hydrogen bonding to enhance the adhesion and permeability of the emulsifiable concentrate on the plant surface, and promote the penetration of the active ingredients through the plant epidermis or the insect body surface, thereby improving the insecticide efficacy. DETAILED DESCRIPTION

[0025] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0026] The sources of some components in the embodiments and comparative examples are as follows: Propylene bromide, CAS No. 41198-08-7, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Cypermethrin, CAS No. 52315-07-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Calcium dodecylbenzenesulfonate, CAS No. 26264-06-2, purchased from Shanghai Huayuan Century Trading Co., Ltd.; Castor oil polyoxyethylene ether, CAS No. 61791-12-6, purchased from Sinopharm Chemical Reagent Co., Ltd.; Peppermint essential oil, product number 0471EIS21, was purchased from Shanghai Zhuben Cosmetics Co., Ltd.; Cinnamon essential oil, product number S33677-1L, was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; Polyethylene glycol, product number P103728, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Carboxymethyl cellulose I, product number C501052, viscosity 800 mPa.s, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Carboxymethyl cellulose II, product number C299502, viscosity 100 mPa.s, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Carboxymethyl cellulose III, product number C104977, viscosity 4000 mPa.s, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Epoxidized soybean oil, CAS No. 8013-07-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Epichlorohydrin, CAS No. 106-89-8, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Triphenyl phosphate, CAS No. 115-86-6, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Ethanolamine, CAS No. 141-43-5, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Triethanolamine, CAS No. 102-71-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Diisopropylamine, CAS No. 108-18-9, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Ethyl acetate, CAS No. 141-78-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Sodium alginate, CAS No. 9005-38-3, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Microcrystalline cellulose, CAS No. 9004-34-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.; L-Malic acid, CAS No. 97-67-6, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Silane coupling agent KH-550, CAS No. 919-30-2, purchased from Zhongshan Dixin Chemical Co., Ltd.; Tween 80, CAS No. 9005-65-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Glycerol, CAS No. 56-81-5, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Calcium chloride, CAS No. 10043-52-4, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Sodium vinyl sulfonate, CAS No. 3039-83-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Acrylic acid, CAS No. 79-10-7, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Ammonium persulfate, CAS No. 7727-54-0, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Chitosan, CAS No. 9012-76-4, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Potassium hydroxide, CAS No. 1310-58-3, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0027] Example 1 This embodiment provides a method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils, comprising the following steps: Preparation of modified microcrystalline cellulose: In parts by weight, 8 parts of microcrystalline cellulose are added to 100 parts of deionized water and ultrasonically dispersed for 3 hours, then 50 parts of L-malic acid are added to react at 96°C for 10 hours, after the reaction is completed, 0.4 parts of silane coupling agent KH-550 are added and ultrasonically dispersed for 4 hours, filtered, washed with water, and dried to obtain modified microcrystalline cellulose.

[0028] Preparation of sulfonated polyethylene glycol: In parts by weight, 8 parts of polyethylene glycol are added to 220 parts of deionized water and stirred to dissolve, and then 6 parts of sodium vinyl sulfonate, 3 parts of acrylic acid and 0.8 parts of ammonium persulfate are added to carry out heating reaction (under a nitrogen atmosphere, the temperature is 90°C, and the time is 60 minutes). After the heating reaction is completed, it is cooled to room temperature and freeze-dried to obtain sulfonated polyethylene glycol.

[0029] Preparation of chitosan-modified carboxymethyl cellulose: In parts by weight, 3 parts of chitosan are added to 120 parts of anhydrous ethanol, and stirred at 500 r / min for 20 minutes to obtain liquid A; 8 parts of potassium hydroxide are added to 1120 parts of deionized water to fully dissolve, and then 6 parts of carboxymethyl cellulose I (viscosity 800 mPa.s) are added and stirred for 4 hours, and then 120 parts of the liquid A are added and stirred at 500 r / min for 4 hours. After stirring, the mixture is washed with anhydrous ethanol and dried to obtain chitosan-modified carboxymethyl cellulose.

[0030] Step S1: by weight, 3 parts of sodium alginate are added to 100 parts of deionized water and stirred for 6 hours to obtain a sodium alginate aqueous solution; 4 parts of peppermint essential oil and 100 parts of anhydrous ethanol are mixed evenly, and then 100 parts of the sodium alginate aqueous solution are added and ultrasonically dispersed for 60 minutes to obtain a peppermint essential oil mixed solution; Step S2: in parts by weight, 20 parts of anhydrous ethanol and 100 parts of deionized water are mixed evenly, and then 4 parts of modified microcrystalline cellulose are added and stirred for 40 minutes, and then 6 parts of cinnamon essential oil, 0.8 parts of Tween 80, 3 parts of glycerol and 3 parts of calcium chloride are added, and the mixture is stirred and mixed for 1 minute at a speed of 8000 r / min using a high-speed shear homogenizer, and vacuum defoaming is performed to obtain a cinnamon essential oil mixture; Step S3: using the peppermint essential oil mixture as a core layer spinning solution and the cinnamon essential oil mixture as a shell layer spinning solution, obtaining a composite material by coaxial electrospinning, freeze-drying, and pulverizing to obtain a plant essential oil compound; The conditions of the coaxial electrospinning are: the syringe propulsion speed of the shell layer spinning solution is 1.0 ml / h, the syringe propulsion speed of the core layer spinning solution is 0.3 ml / h, the needle voltage is 22 kv, the receiving distance is 16 cm, the temperature is 40° C., the humidity is 35%, and the spinning time is 1 hour; Step S4: In parts by weight, 60 parts of ethyl acetate, 4 parts of stabilizer epoxy soybean oil, 20 parts of cypermethrin and 30 parts of bromophos are added into a reactor and stirred for 30 minutes, then 20 parts of emulsifier (12 parts of calcium dodecylbenzene sulfonate and 8 parts of castor oil polyoxyethylene ether), 12 parts of plant essential oil compound, 10 parts of sulfonated polyethylene glycol and 8 parts of chitosan modified carboxymethyl cellulose are added and stirred for 30 minutes, and finally 0.8 parts of pH adjuster ethanolamine is added and stirred for 20 minutes to obtain an insecticide emulsifiable concentrate compounded with plant essential oils.

[0031] Example 2 This embodiment provides a method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils, comprising the following steps: Preparation of modified microcrystalline cellulose: In parts by weight, 4 parts of microcrystalline cellulose are added to 80 parts of deionized water and ultrasonically dispersed for 1 hour, and then 40 parts of L-malic acid are added to react at 90°C for 12 hours. After the reaction is completed, 0.2 parts of silane coupling agent KH-550 are added and ultrasonically dispersed for 2 hours, filtered, washed with water, and dried to obtain modified microcrystalline cellulose.

[0032] Preparation of sulfonated polyethylene glycol: In parts by weight, 6 parts of polyethylene glycol are added to 200 parts of deionized water and stirred to dissolve, and then 4 parts of sodium vinyl sulfonate, 1 part of acrylic acid and 0.6 parts of ammonium persulfate are added to carry out heating reaction (under a nitrogen atmosphere, the temperature is 80°C, the time is 80 minutes), and after the heating reaction is completed, it is cooled to room temperature and freeze-dried to obtain sulfonated polyethylene glycol.

[0033] Preparation of chitosan-modified carboxymethyl cellulose: In parts by weight, 1 part of chitosan is added to 100 parts of anhydrous ethanol, and stirred at 400 r / min for 30 minutes to obtain liquid A; 6 parts of potassium hydroxide are added to 100 parts of deionized water to fully dissolve, and then 2 parts of carboxymethyl cellulose I (viscosity 800 mPa.s) are added and stirred for 2 hours, and then 100 parts of the liquid A are added and stirred at 400 r / min for 6 hours. After stirring, it is washed with anhydrous ethanol and dried to obtain chitosan-modified carboxymethyl cellulose.

[0034] Step S1: by weight, 1 part of sodium alginate is added to 80 parts of deionized water and stirred for 4 hours to obtain a sodium alginate aqueous solution; 2 parts of peppermint essential oil and 80 parts of anhydrous ethanol are mixed evenly, and then 80 parts of the sodium alginate aqueous solution are added and ultrasonically dispersed for 40 minutes to obtain a peppermint essential oil mixed solution; Step S2: in parts by weight, 10 parts of anhydrous ethanol and 80 parts of deionized water are mixed evenly, and then 2 parts of modified microcrystalline cellulose are added and stirred for 30 minutes, and then 2 parts of cinnamon essential oil, 0.6 parts of Tween 80, 1 part of glycerol and 1 part of calcium chloride are added, and the mixture is stirred and mixed for 3 minutes at a speed of 6000 r / min using a high-speed shear homogenizer, and vacuum defoaming is performed to obtain a cinnamon essential oil mixture; Step S3: using the peppermint essential oil mixture as a core layer spinning solution and the cinnamon essential oil mixture as a shell layer spinning solution, obtaining a composite material by coaxial electrospinning, freeze-drying, and pulverizing to obtain a plant essential oil compound; The coaxial electrospinning conditions are as follows: the syringe propulsion speed of the shell layer spinning solution is 0.5 ml / h, the syringe propulsion speed of the core layer spinning solution is 0.1 ml / h, the needle voltage is 18 kV, the receiving distance is 18 cm, the temperature is 30° C., the humidity is 45%, and the spinning time is 2 h; Step S4: In parts by weight, 60 parts of ethyl acetate, 2 parts of stabilizer epichlorohydrin, 16 parts of cypermethrin and 20 parts of bromophos are added into a reactor and stirred for 20 minutes, then 10 parts of emulsifier (5 parts of calcium dodecylbenzene sulfonate and 5 parts of castor oil polyoxyethylene ether), 8 parts of plant essential oil compound, 6 parts of sulfonated polyethylene glycol and 4 parts of chitosan modified carboxymethyl cellulose are added and stirred for 20 minutes, and finally 0.4 parts of pH adjuster triethanolamine is added and stirred for 10 minutes to obtain an insecticide emulsifiable concentrate compounded with plant essential oils.

[0035] Example 3 This embodiment provides a method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils, comprising the following steps: Preparation of modified microcrystalline cellulose: In parts by weight, 6 parts of microcrystalline cellulose are added to 90 parts of deionized water and ultrasonically dispersed for 2 hours, then 45 parts of L-malic acid are added and reacted at 92°C for 11 hours. After the reaction is completed, 0.3 parts of silane coupling agent KH-550 is added and ultrasonically dispersed for 3 hours, filtered, washed with water, and dried to obtain modified microcrystalline cellulose.

[0036] Preparation of sulfonated polyethylene glycol: In parts by weight, 7 parts of polyethylene glycol are added to 210 parts of deionized water and stirred to dissolve, and then 5 parts of sodium vinyl sulfonate, 2 parts of acrylic acid and 0.7 parts of ammonium persulfate are added to carry out heating reaction (under a nitrogen atmosphere, the temperature is 85°C, and the time is 70 minutes). After the heating reaction is completed, it is cooled to room temperature and freeze-dried to obtain sulfonated polyethylene glycol.

[0037] Preparation of chitosan-modified carboxymethyl cellulose: In parts by weight, 2 parts of chitosan are added to 110 parts of anhydrous ethanol, and stirred at 450 r / min for 25 minutes to obtain liquid A; 7 parts of potassium hydroxide are added to 110 parts of deionized water to fully dissolve, and then 4 parts of carboxymethyl cellulose I (viscosity 800 mPa.s) are added and stirred for 3 hours, and then 110 parts of the liquid A are added and stirred at 450 r / min for 5 hours. After stirring, the mixture is washed with anhydrous ethanol and dried to obtain chitosan-modified carboxymethyl cellulose.

[0038] Step S1: by weight, 2 parts of sodium alginate are added to 90 parts of deionized water and stirred for 5 hours to obtain a sodium alginate aqueous solution; 3 parts of peppermint essential oil and 90 parts of anhydrous ethanol are mixed evenly, and then 90 parts of the sodium alginate aqueous solution are added and ultrasonically dispersed for 50 minutes to obtain a peppermint essential oil mixed solution; Step S2: by weight, 15 parts of anhydrous ethanol and 90 parts of deionized water are mixed evenly, and then 3 parts of modified microcrystalline cellulose are added and stirred for 35 minutes, and then 4 parts of cinnamon essential oil, 0.7 parts of Tween 80, 2 parts of glycerol and 2 parts of calcium chloride are added, and the mixture is stirred and mixed for 2 minutes at a speed of 7000 r / min using a high-speed shear homogenizer, and vacuum defoaming is performed to obtain a cinnamon essential oil mixture; Step S3: using the peppermint essential oil mixture as a core layer spinning solution and the cinnamon essential oil mixture as a shell layer spinning solution, obtaining a composite material by coaxial electrospinning, freeze-drying, and pulverizing to obtain a plant essential oil compound; The coaxial electrospinning conditions are as follows: the syringe propulsion speed of the shell layer spinning solution is 0.8 ml / h, the syringe propulsion speed of the core layer spinning solution is 0.2 ml / h, the needle voltage is 20 kv, the receiving distance is 17 cm, the temperature is 35° C., the humidity is 40%, and the spinning time is 2 h; Step S4: In parts by weight, 55 parts of ethyl acetate, 3 parts of stabilizer triphenyl phosphate, 18 parts of cypermethrin and 25 parts of bromophos are added into a reactor and stirred for 25 minutes, then 18 parts of emulsifier (12 parts of calcium dodecylbenzene sulfonate and 6 parts of castor oil polyoxyethylene ether), 10 parts of plant essential oil compound, 8 parts of sulfonated polyethylene glycol and 6 parts of chitosan modified carboxymethyl cellulose are added and stirred for 25 minutes, and finally 0.6 parts of pH adjuster diisopropylamine is added and stirred for 15 minutes to obtain an insecticide emulsifiable concentrate compounded with plant essential oils.

[0039] Comparative Example 1 This comparative example provides a method for preparing an insecticide emulsifiable concentrate, which differs from Example 1 in that commercially available peppermint essential oil is used instead of a peppermint essential oil mixture as a core layer spinning solution to prepare a plant essential oil compound, and the rest is the same as Example 1.

[0040] Comparative Example 2 This comparative example provides a method for preparing an insecticide emulsifiable concentrate, which differs from Example 1 in that commercially available cinnamon essential oil is used instead of a cinnamon essential oil mixture as a shell spinning solution to prepare a plant essential oil compound, and the rest is the same as Example 1.

[0041] Comparative Example 3 This comparative example provides a method for preparing an insecticide emulsifiable concentrate, which differs from Example 1 in that commercially available polyethylene glycol is used instead of sulfonated polyethylene glycol, and the rest is the same as Example 1.

[0042] Comparative Example 4 This comparative example provides a method for preparing an insecticide emulsifiable concentrate, which differs from Example 1 in that carboxymethyl cellulose I is used instead of chitosan-modified carboxymethyl cellulose, and the rest is the same as Example 1.

[0043] Comparative Example 5 This comparative example provides a method for preparing an insecticide emulsifiable concentrate, which differs from Example 1 in that carboxymethyl cellulose II is used instead of carboxymethyl cellulose I to prepare chitosan-modified carboxymethyl cellulose, and the rest is the same as Example 1.

[0044] Comparative Example 6 This comparative example provides a method for preparing an insecticide emulsifiable concentrate, which differs from Example 1 in that carboxymethyl cellulose III is used instead of carboxymethyl cellulose I to prepare chitosan-modified carboxymethyl cellulose, and the rest is the same as Example 1.

[0045] Comparative Example 7 This comparative example provides a method for preparing an insecticide emulsifiable concentrate, which is different from Example 1 in that the amount of calcium dodecylbenzenesulfonate in the emulsifier is changed to 16 parts, and the amount of castor oil polyoxyethylene ether is changed to 4 parts, and the rest is the same as Example 1.

[0046] Comparative Example 8 This comparative example provides a method for preparing an insecticide emulsifiable concentrate, which is different from Example 1 in that the amount of calcium dodecylbenzenesulfonate in the emulsifier is changed to 5 parts, and the amount of castor oil polyoxyethylene ether is changed to 15 parts, and the rest is the same as Example 1.

[0047] The performance of the insecticide emulsifiable concentrate provided in the above embodiments and comparative examples was tested, and the specific testing method is as follows: (1) Thermal storage stability test: The test shall be conducted in accordance with the requirements of GB / T 19136-2021 Method for Determination of Thermal Storage Stability of Pesticides.

[0048] (2) Low temperature stability test: Conduct the test in accordance with the requirements of GB / T 19137-2003 Method for Determination of Low Temperature Stability of Pesticides.

[0049] (3) Insecticide efficacy test: Test according to the requirements of GB / T 13917.1-2009 Indoor efficacy test and evaluation of public insecticides for pesticide registration Part 1: Sprayers.

[0050] The above performance test data is shown in Table 1.

[0051] Table 1 Performance test results

[0052] From the above content, it can be seen that the present invention forms a plant essential oil composite by processing peppermint essential oil and cinnamon essential oil, and combines the use of other functional components, sulfonated polyethylene glycol and chitosan-modified carboxymethyl cellulose, to prepare a plant essential oil composite insecticidal emulsion (Examples 1-3), which has qualified heat storage stability and low temperature stability, and the 24h mosquito mortality rate is 97.5-98.2%.

[0053] Compared with Example 1, commercially available peppermint essential oil was used to replace peppermint essential oil mixture as the core layer spinning solution for preparing the plant essential oil compound. Due to the lack of sodium alginate, the effect was not good, the heat storage stability and low temperature stability became worse, and the insecticidal efficacy was weakened (Comparative Example 1); Compared with Example 1, commercially available cinnamon essential oil was used to replace cinnamon essential oil mixture as the shell layer spinning solution for preparing the plant essential oil compound. Due to the lack of calcium chloride, the effect was not good, the heat storage stability and low temperature stability became worse, and the insecticidal efficacy was weakened (Comparative Example 2); Compared with Example 1, commercially available polyethylene glycol was used to replace sulfonated polyethylene glycol, the heat storage stability and low temperature stability became worse, and the insecticidal efficacy was weakened (Comparative Example 3); Compared with Example 1, carboxymethyl cellulose I was used to replace chitosan-modified carboxymethyl cellulose, the heat storage stability and low temperature stability became worse, and the insecticidal efficacy was weakened (Comparative Example 4); Compared with Example 1, carboxymethyl cellulose II was used to replace carboxymethyl cellulose I for the preparation of chitosan-modified carboxymethyl cellulose, by Because the viscosity of carboxymethyl cellulose II is too small, the modification effect is not good, the heat storage stability and low temperature stability deteriorate, and the insecticide efficacy is weakened (Comparative Example 5); compared with Example 1, carboxymethyl cellulose III is used to replace carboxymethyl cellulose I for the preparation of chitosan-modified carboxymethyl cellulose. Because the viscosity of carboxymethyl cellulose III is too large, the modification effect is not good, the heat storage stability and low temperature stability deteriorate, and the insecticide efficacy is weakened (Comparative Example 6); compared with Example 1, the amount of calcium dodecylbenzene sulfonate in the emulsifier is changed to 16 parts, and the amount of castor oil polyoxyethylene ether is changed to 4 parts. Due to the excessive amount of calcium dodecylbenzene sulfonate, the compounding effect is not good, the heat storage stability and low temperature stability deteriorate, and the insecticide efficacy is weakened (Comparative Example 7); compared with Example 1, the amount of calcium dodecylbenzene sulfonate in the emulsifier is changed to 5 parts, and the amount of castor oil polyoxyethylene ether is changed to 15 parts. Due to the small amount of calcium dodecylbenzene sulfonate, the compounding effect is not good, the heat storage stability and low temperature stability deteriorate, and the insecticide efficacy is weakened (Comparative Example 8).

[0054] In summary, the present invention forms a plant essential oil composite by processing peppermint essential oil and cinnamon essential oil, and combines the use of other functional components, sulfonated polyethylene glycol and chitosan-modified carboxymethyl cellulose, to prepare an insecticidal emulsifiable concentrate compounded with plant essential oils. With the synergistic effect of multiple components, the insecticidal emulsifiable concentrate has good heat storage stability and low-temperature stability, while improving the insecticidal efficacy.

Claims

1. A method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils, characterized in that: The following steps are involved: Step S1: in parts by weight, 1-3 parts of sodium alginate and 80-100 parts of deionized water are stirred evenly to obtain a sodium alginate aqueous solution; 2-4 parts of peppermint essential oil and 80-100 parts of anhydrous ethanol are mixed, and then 80-100 parts of the sodium alginate aqueous solution are added and ultrasonically dispersed to obtain a peppermint essential oil mixed solution; Step S2: 10-20 parts of anhydrous ethanol and 80-100 parts of deionized water are mixed, and then 2-4 parts of microcrystalline cellulose are added and stirred evenly, and then 2-6 parts of cinnamon essential oil, 0.6-0.8 parts of Tween 80, 1-3 parts of glycerol and 1-3 parts of calcium chloride are added and high-speed homogenized to obtain a cinnamon essential oil mixed solution; Step S3: coaxially electrospinning the peppermint essential oil mixture and the cinnamon essential oil mixture to obtain a plant essential oil compound; Step S4: 50-60 parts of ethyl acetate, 2-4 parts of stabilizer, 16-20 parts of cypermethrin and 20-30 parts of bromophos are stirred evenly, 10-20 parts of emulsifier, 8-12 parts of plant essential oil compound, 6-10 parts of sulfonated polyethylene glycol and 4-8 parts of chitosan-modified carboxymethyl cellulose are added and mixed evenly, and finally 0.4-0.8 parts of pH regulator are added to obtain an insecticide emulsifiable concentrate compounded with plant essential oil; The preparation method of the sulfonated polyethylene glycol comprises: adding 6 to 8 parts of polyethylene glycol to 200 to 220 parts of deionized water, stirring and dissolving, then adding 4 to 6 parts of sodium vinyl sulfonate, 1 to 3 parts of acrylic acid and 0.6 to 0.8 parts of ammonium persulfate for heating reaction, and freeze drying to obtain the sulfonated polyethylene glycol; The preparation method of chitosan-modified carboxymethyl cellulose comprises: adding 1-3 parts of chitosan to 100-120 parts of anhydrous ethanol to obtain liquid A, adding 6-8 parts of potassium hydroxide to 100-120 parts of deionized water to fully dissolve, adding 2-6 parts of carboxymethyl cellulose and 100-120 parts of the liquid A to stir and obtain chitosan-modified carboxymethyl cellulose.

2. The method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils according to claim 1, characterized in that: The microcrystalline cellulose is modified microcrystalline cellulose; The preparation method of the modified microcrystalline cellulose comprises: adding 4 to 8 parts of microcrystalline cellulose to 80 to 100 parts of deionized water by weight for ultrasonic dispersion for 1 to 3 hours, then adding 40 to 50 parts of L-malic acid for reaction at 90 to 96° C. for 10 to 12 hours, adding 0.2 to 0.4 parts of silane coupling agent KH-550 for ultrasonic dispersion for 2 to 4 hours after the reaction is completed, filtering, washing with water, and drying to obtain the modified microcrystalline cellulose.

3. The method for preparing a compound insecticide emulsifiable concentrate of plant essential oil according to claim 1, characterized in that: The conditions of the high-speed homogenization treatment in step S2 include: stirring and mixing for 1 to 3 minutes at a speed of 6000 to 8000 r / min using a high-speed shear homogenizer, and then performing vacuum defoaming.

4. The method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils according to claim 1, characterized in that: The heating reaction conditions include: under a nitrogen atmosphere, a temperature of 80-90° C., and a time of 60-80 min.

5. The method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils according to claim 1, characterized in that: The stirring treatment conditions include: stirring at 400-500 r / min for 6-8 hours, washing with anhydrous ethanol after the stirring is completed, and drying.

6. The method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils according to claim 1, characterized in that: The viscosity of the carboxymethyl cellulose is 500-1000 Pa.s.

7. The method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils according to claim 1, characterized in that: The coaxial electrospinning conditions are as follows: the peppermint essential oil mixture is used as the core layer spinning solution, the cinnamon essential oil mixture is used as the shell layer spinning solution, the syringe propulsion speed of the shell layer spinning solution is 0.5-1.0 ml / h, the syringe propulsion speed of the core layer spinning solution is 0.1-0.3 ml / h, the needle voltage is 18-22 kv, the receiving distance is 16-18 cm, the temperature is 30-40° C., the humidity is 35-45%, the spinning time is 1-2 h, and freeze-drying is performed after spinning is completed.

8. The method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils according to claim 1, characterized in that: The emulsifier is calcium dodecylbenzene sulfonate and castor oil polyoxyethylene ether; the mass ratio of calcium dodecylbenzene sulfonate and castor oil polyoxyethylene ether is (1-2):

1.

9. The method for preparing an insecticide emulsifiable concentrate compounded with plant essential oils according to claim 1, characterized in that: The stabilizer is selected from any one of epoxy soybean oil, epichlorohydrin, and triphenyl phosphate, or a combination of at least two thereof; and the pH adjuster is selected from any one of ethanolamine, triethanolamine, and diisopropylamine, or a combination of at least two thereof.

10. An insecticide emulsifiable concentrate compounded with plant essential oils, characterized in that: Prepared according to the method according to any one of claims 1 to 9.

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