US-12617736-B2 - Granular fertilizers and methods of making same

Abstract

Coated granules and methods of making the coated granules that prevent the coated granules from floating and/or drifting due to water current and wind are disclosed. The coated granules may include a core having a water-soluble compound, such as a fertilizer; a controlled release layer; a surface treatment including a surfactant to reduce water tension; and an optional coating disposed between the controlled release layer and the surface treatment layer that includes a gelling agent, such as a super absorbent polymer, that may help to anchor the coated granules to the surface of the soil and reduces the chance of relocation due to rolling.

Inventors

• Timothy Gene Holt
• Trenton Cole Gillis

Assignees

• Pursell Agri-Tech, LLC

Dates

Publication Date

20260505

Application Date

20220309

Claims (20)

1. 1 . A coated fertilizer granule, comprising: a core comprising a water-soluble fertilizer material; a coating comprising a urethane layer impregnated with a gelling agent; a controlled release layer disposed between the core and the coating; and a surface treatment layer disposed on the coating and comprising a surfactant and a solvent, wherein the surfactant comprises alkyl polyglycoside, ethoxylated sorbitan ester, polyhydric alcohol, or a combination thereof.
2. 2 . The coated fertilizer granule of claim 1 , wherein the urethane layer is formed from a reaction product of one or both of (i) a polyol blended with the gelling agent and reacted with isocyanate, and/or (ii) an isocyanate blended with the gelling agent reacted with polyol.
3. 3 . The coated fertilizer of claim 1 , wherein the surfactant comprises a blend of alkyl polyglycoside, ethoxylated sorbitan ester, and polyhydric alcohol.
4. 4 . The coated fertilizer of claim 1 , wherein the solvent is selected from dipropylene glycol, tripropylene glycol, glycerin, propylene carbonate, vegetable oil, and combinations thereof.
5. 5 . The coated fertilizer granule of claim 1 , wherein the gelling agent is a super absorbent polymer.
6. 6 . The coated fertilizer granule of claim 1 , wherein the gelling agent comprises a polyacrylamide, polyacrylate, vegetable starch, bentonite clay, or montmorillonite clay.
7. 7 . The coated fertilizer granule of claim 1 , wherein the gelling agent comprises a water absorbent polymer with a water retention ability of at least about 20 g water per g absorbent polymer.
8. 8 . The coated fertilizer granule of claim 1 , wherein the water-soluble fertilizer material comprises a primary nutrient comprising urea, ammonium sulfate, calcium nitrate, diammonium phosphate, monoammonium phosphate, potassium nitrate, sodium nitrate, single superphosphate, triple superphosphate, calcium phosphate, monopotassium phosphate, dipotassium phosphate, tetra-potassium pyrophosphate, potassium metaphosphate, potassium chloride, potassium nitrate, potassium sulfate, or combinations thereof.
9. 9 . The coated fertilizer granule of claim 8 , wherein the water-soluble fertilizer material further comprises a secondary nutrient comprising calcium sulfate, calcium chloride, calcium carbonate, calcium silicate, calcium phosphate, magnesium sulfate, magnesium chloride, magnesium oxide, magnesium carbonate, elemental sulfur, ammonium sulfate, or combinations thereof.
10. 10 . A fertilizer granule, comprising: a core comprising a water-soluble fertilizer material; a surface treatment layer comprising a surfactant and a solvent, wherein the surfactant comprises alkyl polyglycoside, ethoxylated sorbitan ester, polyhydric alcohol, or a combination thereof; and a controlled release layer disposed between the core and the surface treatment layer, wherein the controlled release layer comprises at least one urethane layer and at least one wax layer.
11. 11 . The fertilizer granule of claim 10 , wherein the controlled release layer comprises a plurality of alternating urethane and wax layers.
12. 12 . The fertilizer granule of claim 11 , wherein the thickness of the controlled release layer is about 1 μm to about 150 μm.
13. 13 . The fertilizer granule of claim 10 , further comprising a coating disposed between the controlled release layer and the surface treatment layer.
14. 14 . The fertilizer granule of claim 10 , wherein the surfactant comprises a blend of alkyl polyglycoside, ethoxylated sorbitan ester, and polyhydric alcohol.
15. 15 . The fertilizer granule of claim 10 , wherein the solvent is selected from dipropylene glycol, tripropylene glycol, glycerin, propylene carbonate, vegetable oil, and combinations thereof.
16. 16 . A method of making a coated fertilizer granule, comprising: providing a core comprising a water-soluble fertilizer material; applying a controlled release layer disposed over the core to form a controlled release core; applying a coating over the controlled release core to form a coated core, wherein the coating comprises a urethane layer impregnated with a gelling agent; and applying a surface treatment layer over the coated core, the outer surface treatment layer comprising a surfactant and a solvent, wherein the surfactant comprises alkyl polyglycoside, ethoxylated sorbitan ester, polyhydric alcohol, or a combination thereof.
17. 17 . The method of claim 16 , wherein the urethane layer is formed from a reaction product of one or both of (i) a polyol blended with the gelling agent and reacted with isocyanate, and/or (ii) an isocyanate blended with the gelling agent and reacted with polyol.
18. 18 . The method of claim 16 , wherein the gelling agent comprises a super absorbent polymer.
19. 19 . The method of claim 16 , wherein the water-soluble fertilizer material comprises a water-soluble pesticide.
20. 20 . The method of claim 16 , wherein the solvent is selected from dipropylene glycol, tripropylene glycol, glycerin, propylene carbonate, vegetable oil, and combinations thereof.

Description

TECHNICAL FIELD The present disclosure relates generally to granular fertilizers and methods of making and using the same. More specifically, the present disclosure relates to coated fertilizer granules with a core including a water-soluble fertilizer material, a controlled release layer, an optional coating layer, and an outer surface treatment layer. BACKGROUND While there have been significant improvements in producing controlled release fertilizers, there is still a need for further advancements as it relates to crops that are grown in flooded conditions. For example, many of the coated fertilizers currently on the market share one common undesirable trait: they float. Once the coated granules begin to float, the water current and/or wind transports the fertilizer to areas low in plant population, and the areas of increased plant population cannot take advantage of the benefits provided by the controlled release fertilizer. The polymers and wax that generally make up the outer barriers of the fertilizers are very hydrophobic and will cause the granules to become buoyant. Large quantities of once uniformly distributed coated fertilizers on a farmer's field are relocated to the lowest elevation of the area. This undesirable occurrence is very common when farmers attempt to use coated fertilizers on pre-flood or post-flooded fields. Accordingly, there remains a need in the art for preventing coated fertilizers from floating and drifting due to water current and wind. SUMMARY The problems expounded above, as well as others, are addressed by the following inventions, although it is to be understood that not every embodiment of the inventions described herein will address each of the problems described above. The present disclosure provides coated granules and methods of making the coated granules that facilitate one or both of sinking and sticking to the underlying surface (such as soil). The coated granules include a gelling agent that serves to anchor the coated granules to the surface of the soil and reduces the chance of relocation due to rolling. Some embodiments of the granule include an exterior wetting agent, such as a surfactant, that facilitates sinking. In a first aspect, a coated fertilizer granule is provided, the coated fertilizer granule including a core that includes a water-soluble fertilizer material, a coating comprising a urethane layer impregnated with a super absorbent polymer, wherein the urethane layer is formed from a reaction product of one or both of (i) a polyol blended with the super absorbent polymer and reacted with isocyanate, and/or (ii) an isocyanate blended with the super absorbent polymer reacted with polyol; a controlled release layer disposed between the core and the coating; and a surface treatment layer disposed about the coating that includes a surfactant and a solvent. In a second aspect, a coated granule is provided, the coated granule including a core that includes a water-soluble compound; a coating including a gelling agent; a controlled release layer between the core and the coating; and a surface treatment layer disposed about the coating that includes a surfactant and a solvent. In a third aspect, a coated granule is provided, the coated granule including a urethane coating impregnated with an absorbent polymer and a core, wherein the urethane coating is formed from a reaction product of one or both of: (i) a polyol blended with the absorbent polymer and reacted with isocyanate; and (ii) an isocyanate blended with the absorbent polymer reacted with polyol. In one embodiment, the granule includes a core that includes a water soluble fertilizer material. In another embodiment, the granule includes a surface treatment layer disposed about the coating formed from a surfactant and a solvent. In a fourth aspect, a fertilizer granule is provided that includes a core including a water-soluble fertilizer material, a controlled release layer disposed about the core; and a surface treatment layer disposed about the controlled release layer that includes a surfactant and a solvent. In any of the above aspects, the surfactant may be an alcohol ethoxylate, a silicone-based surfactant, or a combination thereof. In another embodiment, the surfactant may be alkyl polyglycoside, ethoxylated sorbitan ester, polyhydric alcohol, or a combination thereof. In yet another embodiment, the surfactant is a blend of alkyl polyglycoside, ethoxylated sorbitan ester, and polyhydric alcohol. In any of the above aspects, the solvent may be tripropylene glycol. In a fifth aspect, a method of making a coated fertilizer granule is provided, the method including providing a core that includes a water-soluble fertilizer material; applying a controlled release layer disposed over the core; applying a coating over the controlled release layer, the coating including a urethane layer impregnated with a super absorbent polymer, wherein the urethane layer is formed from a reaction product of one or both