MICROCAPSULATED AGRICULTURAL COMPOSITIONS

摘要

Agriculturally active materials, such as pesticides, herbicides and the like and a process for microencapsulating said materials. The present invention includes trifluralin having a polymorphic form characterized by a yellow color and a melting point of approximately 41 DEG -- 43 DEG C. The present invention also includes a method of using the yellow polymorphic form of trifluralin as a herbicide. In addition, the present invention includes a method of microencapsulating low-melting agricurally active materials, such as trifluralin. The microencapsulation process comprises the steps of heating a low-melting, water-immiscible, agricurally active material to a molten state. The molten active material is then combined with an aqueous solution of a water-soluble, film-forming polymer at a temperature sufficient to maintain the active material in its molten state. The active material is then dispersed or emulsified in the aqueous solution so that the active material has a primary particle size of between approximately 0.1 and 10 microns. The resulting dispersion or emulsion is then spray dried at a temperature between approximately 50 DEG and 220 DEG C. so as to microencapsulate the active material in the polymer. Compounds for promoting the rapid solidification of the active material are also disclosed.