Cross-linked polyols for controlled release fertilizers
AssigneeAgrium Advanced Technologies
InventorsSrirakrishna Maruvada, Nick Peter Wynnyk, Baozhong Xing
Life of this patent
Estimating the term…
Abstract
A controlled release fertilizer material comprising a particulate plant nutrient surrounded by a coating including a mixture of a cross-linked polyol and an isocyanate, and optionally a wax, is described. In some embodiments, the cross-linked polyol can be cross-linked with sulfur, oxygen, and/or a peroxide cross-linking moiety. In one embodiment the cross-linked polyol is castor oil cross-linked with sulfur.
Claims18
A controlled release fertilizer composition comprising a particulate plant nutrient coated with a coating comprising an isocyanate and a modified polyol, wherein the modified polyol comprises at least one cross-linked polyhydroxyl compound.
A controlled release fertilizer composition comprising a particulate plant nutrient coated with a coating comprising an isocyanate and a modified polyol, wherein the modified polyol comprises at least one polyhydroxyl compound cross-linked with at least one unsaturated wax.
A process of producing a controlled release fertilizer comprising the steps of:
- contacting a polyhydroxyl compound with a cross-linking moiety comprising sulfur, oxygen and/or peroxide of up to about 25 wt. % based on the weight of the mixture of the polyhydroxyl compound to provide a modified polyol;
- contacting a particulate plant nutrient with a mixture comprising the modified polyol and an isocyanate to provide a coated particulate plant nutrient;
- and
- curing the coated particulate plant nutrient to provide the controlled release fertilizer.
A process of producing a controlled release fertilizer comprising the steps of:
- contacting a polyhydroxyl compound and an unsaturated wax with a cross-linking moiety comprising sulfur, oxygen and/or peroxide of up to about 25 wt. % based on the weight of the mixture of the polyhydroxyl compound to provide a modified polyol;
- contacting a particulate plant nutrient with a mixture comprising the modified polyol and an isocyanate to provide a coated particulate plant nutrient;
- and
- curing the coated particulate plant nutrient to provide the controlled release fertilizer.
Dependencies are inferred from the claim text.