Attrition resistant controlled release fertilizers
US4711659A · kind A · utility
Inventor
Key dates
| Filing date | Aug 18, 1986 |
| Grant date | Dec 8, 1987 |
| Priority date | — |
| Expiry date | Aug 18, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC05C9/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
An attrition resistant controlled release fertilizer comprising: NH.sub.2 -containing water soluble central particles such as urea, surrounded and chemically bonded with a base coating, consisting of substituted ureas, formed by reacting a molecular excess of polyfunctional isocyanate with the NH.sub.2 groups of the central particles, and a water insoluble layer, surrounding and chemically bonded with the base coating, formed by the reaction and polymerization of the excess isocyanate with anhydrous organic polyols. If desired, 1 to 10 water insoluble coatings may surround the sealing layer. The base coating's substituted ureas may be effectively formed with diphenylmethane diisocyanate and the sealing layer, with polyethyleneterephthalate polyester polyols containing triethanolamine or melamine catalyst. Central particles effectively coated include: urea, biuret, ureaform, guanidine, melamine, and ammonium salts. A preparation method is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.