| 摘要 |
This invention relates to polyurethane encapsulated fertilizer particles which exhibit slow-release properties and to a process for their production. The process comprises (1) applying an isocyanate-reactive component or a polyisocyanate component to fertilizer particles, to form coated fertilizer particles, followed by (2) applying a polyisocyanate component or an isocyanate-reactive component onto the coated fertilizer particles to form polyurethane encapsulated fertilizer particles, and, optionally, repeating these steps as many times as necessary to form the polyurethane encapsulated fertilizer particles that contain about 2 to 20% by weight of polyurethane, based on the total weight of the encapsulated fertilizer particles. Alternatively, the isocyanate-reactive component and the polyisocyanate component can be premixed prior to being applied to the fertilizer particles to form polyurethane encapsulated fertilizer particles. Suitable isocyanate-reactive components comprise oleo polyols. |
