| 摘要 |
PURPOSE: To obtain separated microcapsules each having a prescribed surface and a prescribed particle size and extremely suitable for preparing pesticidal formulations in a highly simple operation without requiring an additional dispersing agent. CONSTITUTION: The microcapsules containing a water-miscible herbicide (preferably a herbicide such as urea, sulfonyl urea, chloroacetanilide or triazine compound, an insecticide or acaricide such as thiourea, or a germicide) or an easily volatile solvent are obtained by rapidly stirring an aqueous solution of a precondensate of urea and formaldehyde in the molar ratio of 1:3.0 to 1:3.5, especially 1:2.9 to 1:3.1, in an acidified aqueous dispersion of the water- immiscible herbicide or easily volatile solvent. The solvent can be removed from the capsules by a simple method or by a conventional fluidized bed drying method, and the obtained hollow microcapsules are suitable for encapsulating a liquid or a pesticide having a low melting point. |
