Preparation method of environmentally-friendly pyrethrin controlled-release microspheres

Abstract

The invention discloses a preparation method of environmentally-friendly pyrethrin controlled-release microspheres. The method comprises the following steps: (1) performing ultrasonic cleaning on magnetic nanoparticles, and adding ethanol to prepare a magnetic nanoparticle solution; (2) dissolving half of the magnetic nanoparticle solution, a pyrethrin original drug and an environmentally-friendlyhigh-molecular polymer into an oil phase; (3) dissolving the other half of the magnetic nanoparticle solution and an emulsifying agent into a water phase; (4) performing magnetization on the oil phase and the water phase to make the oil phase and the water phase have opposite magnetism; (5) extruding the magnetized oil phase and water phase at a synchronous speed into a supercritical CO2 solvent;(6) adding an antifoaming agent dropwise, and performing a reaction for 12-14 h; (7) performing reduced-pressure drying to obtain controlled-release pyrethrin microspheres; and (8) preparing the pyrethrin sustained-release microsphere wettable powder. According to the preparation method provided by the invention, the pyrethrin controlled-release microspheres prepared by the method have uniform particles and a long lasting period, can reduce frequency of pesticide application and a total amount of the pesticide application, prolong a pesticide application interval, and improve a utilization rate of a pesticide.

Description

technical field [0001] The invention belongs to the technical field of insecticides, and in particular relates to a preparation method of environment-friendly pyrethrin controlled-release microspheres. Background technique [0002] Pyrethrum is a kind of perennial herb in the genus Chrysanthemum of Compositae. Six kinds of insecticidal active ingredients of pyrethrin (trade name: natural pyrethrin) can be extracted from its dried flowers. Appearance: light yellow oily liquid, insoluble in water, soluble in ethanol, petroleum ether, carbon tetrachloride, dichloromethane and other solvents; contains six kinds of insecticidal active ingredients, has the special effect of killing insects quickly, and can be widely used It is widely used in agricultural, forestry, animal husbandry production and urban garden pest control and other fields. It can be widely used in the pest control of economic crops such as green vegetables, fruits, green tea and the like when it is prepared as a ...

AI Technical Summary

Problems solved by technology

These traditional dosage forms are developed for chemical pesticides with relatively single ingredients, while the traditional emulsifiable concentrates and water formulations developed from botanical pesticides with complex active ingredients are easily affected by environmental factors such as leaching, evaporation, degradation, and biology. The rate is often only 30%-40%, which leads to a decrease in the control effect and an increase in the application cost, and the large-scale application of organic solvents not only affects the effective activity of the preparation, but also poses a great threat to the environment

Therefore, at present, the pesticides used in vegetables in my country generally have problems such as large residues, short application time, and large environmental impact.

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