Double coated granules for agricultural use - allow rapid release of active cpds. e.g. insecticide or fungicide, starting several weeks after spreading, timed by appropriate choice of coating polymers.

摘要

Compsn. (A) comprises a nucleus contg. an agricultural chemical, a primary coating of a hydrophilic polymer which swells by water absorption and a second coating of an olefinic polymer, polyamide, polyester, polyether or polyimide. Also claimed is a compsn. (B) comprising a nucleus contg. an agricultural chemical with a primary coating of an alkaline material and a second coating of a mixt. of a polymer soluble in aq. alkali and an olefinic polymer, polyamide, polyester, polyether, or polyimide. USE/ADVANTAGE - Water absorption by the coated granules causes rupture and release of the agricultural chemical. Choice of coatings determines how long after application this takes place. It is possible to make one application of a coated granule mixt. which will release the agricultural chemicals at several stages during crop growth, hence reducing labour. The active chemical may have a neutral support or be combined with a fertilizer. The active chemical may be an insecticide, fungicide, etc.