Process for the production of biodegradable encapsulated fertilizers

This invention relates to a process for producing encapsulated fertilizers which are biodegradable. This process comprises applying at least one coat of an isocyanate-reactive component comprising at least one polyester polyol or at least one polyether polyol to fertilizer particles, and applying at least one coat of an organic polyisocyanate to fertilizer particles, thus forming polyurethane encapsulated fertilizer particles. The present invention also relates to the encapsulated fertilizers produced by this process. This invention relates to a process for the preparation of polyurethane encapsulated fertilizer particles. This process comprises applying an isocyanate-reactive component to fertilizer particles, and applying an aliphatic polyisocyanate to fertilizer particles in separate steps to form polyurethane encapsulated fertilizer particles. The two reactants may be applied in either order, with the polyisocyanate being first or last. These two steps may optionally be repeated as many times, as necessary to yield polyurethane encapsulated fertilizer particles which contain from 0.5 to 15% by weight of polyurethane, based on the total weight of the encapsulated fertilizer particles. It is also possible to mix the isocyanate-reactive component and the polyisocyanate together to form a mixture which is then applied to the fertilizer particles. These polyurethane coatings which encapsulates the fertilizer particles are biodegradable.