Granulated fertilizer with controlled release of nutrients

摘要

Granular fertilizer with controlled release of nutrients can be prepared by coating the fertilizer granules with a mixture of epoxide resin with low molecular weight between 100 and 400 in the amount of 50 to 85 % w/w, imidazole derivative in the amount of 1 to 20 % w/w and modified vegetable oil in the amount of 10 to 30 % w/w. The epoxide resin with low molecular weight between 100 and 400 is preferably bisphenol A diglycidyl ether with epoxide equivalent of 182-192 g/mol, imidazole derivative is preferably 2-ethyl-4-methylimidazole and modified vegetable oil is preferably methylester of rape oil. The coating mixture contains preferably 77.3 % w/w of epoxide resin, 3.4 % w/w of imidazole derivative and 19.3 % w/w of methylester of rape oil, and the fertilizer is coated by gradual spraying of 3 to 20 doses of the coating mixture, wherein the coating is performed in the rotary cylindrical container or fluid apparatus at the temperature of 60 to 120 °C, preferably 105 to 115 °C. The layer of coating mixture makes 6 to 25 % w/w of the overall weight of the coated granule.