Study on preparation of urea-formaldehyde resin microcapsules of Clomazone herbicide

Microcapsules with a urea-formaldehyde resin wall were prepared for clomazone herbicide by in-situ polymerization method in aqueous medium.The factors that affect the size and distribution of microcapsules particles,the ratio of core material and structural characteristics etc.were discussed.The optimal condition of polymerization can be concluded as following: the skin-core ratio is 1∶1.5,the end point pH value is 3.5,and the acidification time is 3 h.Under these conditions,the well microencapsulated fluidizable solid particles were prepared.The distribution of particle size is uniform and the average particle diameter is about 1 μm and the ratio of core material is 26.7%.