Preparation method for fenitrothion microcapsules

Abstract

The invention relates to a preparation method for fenitrothion microcapsules. The preparation method comprises the following steps: firstly, carrier preparation is carried out, namely, a polymerization reaction with a mol ratio of succinic acid, butylene glycol and lactic acid being 1:1:0.2-0.3 is carried out, and a carrier PBS-co-PLA is obtained; secondly, oil phase preparation is carried out, namely, PBS-co-PLA, fenitrothion and dichloromethane are weighed with a mass ratio of PBS-co-PLA, fenitrothion and dichloromethane being 3.5-4.5:1:10, the PBS-co-PLA carrier is dissolved in dichloromethane, after the PBS-co-PLA is dissolved in dichloromethane fully, the fenitrothion active compound is added and dissolved and an oil phase is obtained; thirdly, water phase preparation is carried out, deionized water is measured and taken with a mass ratio of the oil phase to the water phase being 1:5-7, an emulsifier dispersant is added in water and dissolved and a water phase is obtained; fourthly, microcapsule preparation is carried out, namely, the oil phase is added in the water phase, an oil and water mixed emulsion is obtained, an antifoaming agent is added, microcapsule suspension is prepared after curing, water washing is carried out, the supernatant is removed, and a finished product is obtained after drying. The method is simple in technology and is environmentally friendly. The obtained fenitrothion microcapsules have a good form, the encapsulation efficiency is 78%, the drug loading capacity is 50%, the effective release period is 30 days, the drug release amount is 94%, and the fenitrothion microcapsule is an ideal pesticide sustained release agent.

Description

technical field [0001] The invention belongs to the technical field of pesticide preparation, and in particular relates to a preparation method of fenitrothion microcapsules. Background technique [0002] Fenitrothion (fenitrothion) is an organophosphorus insecticide. Moderate toxicity, low toxicity to humans and animals, the acute oral LD50 of rats is 400-800 mg / kg, and the acute percutaneous LD50 of rats is 1200 mg / kg. Fenitrothion has contact killing and stomach poisoning effects, no systemic and fumigation effects, medium residual effect period, wide insecticidal spectrum, special effect on Lepidoptera larvae, and can also control Hemiptera, Coleoptera and other pests. The drug is stable to light, and it is easy to decompose and fail when exposed to high temperature. It is hydrolyzed in alkaline medium, and iron, tin, aluminum, copper, etc. will cause the drug to decompose. It can be stored in glass bottles for a long time. [0003] Microcapsules (Microcapsules, MC) ar...

AI Technical Summary

Problems solved by technology

Since then, the research and development of microcapsules has carried out a lot of basic research in agriculture, and has made some progress. At present, more than 200 agrochemical companies are conducting research on the development and application of microcapsules. It has a history of more than 40 years, but compared with the field of pharmaceutical microcapsules, its development is relatively slow. At present, there are few commercialized pesticide microcapsules.

[0006] The methods of pesticide microencapsulation mainly include interfacial polymerization method, condensed phase separation method, in-situ polymerization method, solvent evaporation method, etc., and these methods are not only complicated in process and high in cost, but also use a large amount of organic solvents, polluting the environment