SLOW-RELEASE POLYURE-THANE (UREA) ENCAPSULATED FERTILIZER

摘要

This invention relates to polyurethane(urea) encapsulated fertilizer particles which exhibit slow-release properties and to a process for their production. In one embodiment, the process comprises a) applying a polyisocyanate component to fertilizer particles to form isocyanate coated fertilizer particles, b) mixing an inert inorganic filler with said isocyana te coated fertilizer, c) adding an isocyanate-reactive component to the mixture of step b) and d) allowing the reactive components to react to form filler containing polyurethane(urea) encapsulated fertilizer particles containing from about 1 to about 15 percent by weight of filled polyurethane(urea), said percent by weight based on the total weight of the encapsulated fertilizer, with the proviso that the weight ratio of polyurethane(urea) to filler is from about 80:20 to about 30:70.