用脲醛树脂制备溴氰菊酯农药微胶囊

Urea-Formaldehyde Resin Microencapsulation of Deltamethrin Pesticide

研究了以水为介质的原位聚合法制备以脲醛树脂为壁材的溴氰菊酯农药微胶囊的缩聚反应工艺。讨论了反应介质的pH值、催化剂、酸化时间和固化温度对微胶囊粒径及其分布、微胶囊结构的影响。结果表明,以NH4Cl做酸性催化剂,酸化时间3h,终点pH值2.0,固化温度70℃,固化时间2h。可制得包覆良好、粒径分布均匀且粒径小于10m的流动性球形固体微胶囊。与乳油相比,微胶囊性能稳定,运输及施用方便并具有良好的缓释性能。

Microcapsules with a urea-formaldehyde resin wall were prepared for deltamethrin by an in situ condensationpolymerization reaction in aqueous medium. Several reaction parameters were investigated, including the effects ofreaction medium pH, catalyst, acidification time, and reaction temperature on size, particle size distribution, andmicrocapsule structure. Optimum reaction conditions were as follows: acidification time 3h, endpoint pH 2.0, curingtemperature 70C, and curing time 2h with NH4Cl as acid catalyst. Under these conditions, solid, spherical microencapsulesformed with uniform diameter of <10m and good flowability. Compared with emulsifiable concentrates, microcapsulesare more stable, easier to use and transport, as well as having excellent slow release properties.