UNSYMMETRICAL POLYUREA-URETHANE FERTILIZER ENCAPSULATION

摘要

This invention relates to processes for the production of unsymmetrical polyurea-urethane coated granular fertilizer products, and to the unsymmetrical polyurea-urethane coated granular fertilizer products produced by these processes. These processes comprise coating fertilizer granules with compounds which react to form unsymmetrical polyurea-urethane coatings, then the compounds are polymerized. Suitable compounds comprise a) an organic polyisocyanate component, and b) an alkanolamine component containing at least one primary or secondary amine group and at least one hydroxyl group. These compounds are present in sufficient quantities that the NCO to active hydrogen group is from about 0.5:1.0 up to about 1.5:1.0. It is necessary that sufficient amounts of these compounds are applied to the fertilizer granules such that the unsymmetrical polyurea-urethane coated granular fertilizer particles contain from about 0.5 to about 15% by weight of polyurea-urethane, based on the total weight of the encapsulated fertilizer particles.