Pesticide microcapsule with easily-adjusted release rate and preparation method of pesticide microcapsule

Abstract

The invention discloses a pesticide microcapsule with an easily-adjusted release rate. The pesticide microcapsule comprises a capsule core and a capsule material; the capsule material is polyurethaneobtained by cross-linking curing of isocyanate, a polyurethane soft segment and a chain extender, and the capsule material accounts for 2%-40% by mass of the pesticide microcapsule; and the capsule core includes an oil-soluble pesticide and an organic solvent, wherein the organic solvent accounts for 0-45% by mass of the pesticide microcapsule. According to the pesticide microcapsule provided by the invention, the oil-soluble pesticide is used as the capsule core and can cooperate with the capsule material in the preparation process to form the structurally-stable pesticide microcapsule; and the capsule material is obtained by a curing cross-linking reaction of the isocyanate, the polyurethane soft segment and the chain extender, the reaction speed is easy to control, and therefore the release rate of the pesticide microcapsule can be conveniently adjusted.

Description

technical field [0001] The invention relates to the technical field of designing pesticide microcapsules, more specifically, designing a method for preparing pesticide microcapsules that is easy to adjust the release rate. Background technique [0002] Pesticide microcapsules refer to pesticide dosage forms that use natural or synthetic polymer materials to form core-shell structure micro-containers, and then coat pesticides in them. They can control the release rate of active ingredients according to the needs of use and the use environment, thereby reducing the toxicity of pesticides. It has the advantages of low toxicity to the environment and human body, good stability of active ingredients and high safety to crops. However, due to the mismatch of the technical parameters of the traditional microcapsule products, the release rate is too slow, so that the release concentration is lower than the effective concentration, which leads to poor drug efficacy (especially the ini...

AI Technical Summary

Problems solved by technology

Most of the capsule wall materials used in pesticide microcapsules in current reports form polyurea capsule shells through interfacial polymerization of diisocyanate and small molecule amines. Due to the influence of factors such as temperature and reaction time, the polymerization reaction rate of the capsule material is not easy to control. If the polymerization reaction is too fast, it will cause aggregation, and if the polymerization reaction is too slow, it will cause capsule rupture, making the batch quality of the prepared microcapsule product unstable; and due to The capsule material of the obtained microcapsule product is a hard microporous structure, which makes it difficult to control the release rate

Moreover, it has been reported in the literature that the release method of this microcapsule is that the active ingredient of the capsule core diffuses or overflows from the micropores of the capsule wall, or the capsule wall is ruptured by environmental pressure, so that the release rate can only be changed by the capsule thickness or particle size.

At the same time, the field environment for actual application of pesticides is complex and changeable. As a method of controlling the release of pesticides after application, pesticide microcapsules need to adjust their release speed according to the growth characteristics of crops and the use environment in order to achieve better drug efficacy. It is difficult to obtain the desired release rate and release mode by changing the capsule thickness or microcapsule particle size

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