Coated granular fertilizer and method for producing same
US6176891A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1998 |
| Grant date | Jan 23, 2001 |
| Priority date | — |
| Expiry date | Mar 26, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G18/8051
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention relates to a coated granular fertilizer having a film covering fertilizer granules. This film comprises a polyurethane resin prepared by a method comprising the steps of (a) reacting an aromatic polyisocyanate with a first polyol component (i.e., castor oil or a castor oil derivative), thereby to obtain a prepolymer having terminal isocyanate groups in the molecule; and (b) reacting the prepolymer with a second polyol component (i.e., castor oil or a castor oil derivative) and a third polyol component which is an amine having at least two hydroxyl groups in the molecule, thereby to cure the prepolymer and thus to prepare the polyurethane resin. The invention relates to another coated granular fertilizer having a film covering fertilizer granules. This film comprises a urethane resin and aqueous-fluid-absorbing particles having a particle diameter of from 1 to 200 .mu.m. This urethane resin may be the above polyurethane resin. This coated granular fertilizer can be produced by a method comprising the steps of (a) applying an aromatic polyisocyanate, a polyol component (i.e., castor oil or a castor oil derivative), an amine, and the aqueous-fluid-absorbing particles, at…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.