Controlled release fertilizers made from cross-linked glyceride mixtures
A controlled release fertilizer material comprising a particulate plant nutrient surrounded by a coating which is the reaction product of a mixture including a cross-linked polyol, an isocyanate and a wax is described. The cross-linked polyol is a reaction product of a polyhydroxyl compound, such as glycerol, and a triglyceride and the monoglyceride and/or diglyceride products are cross-linked with sulfur, oxygen and/or a peroxide cross-linking moiety, or are directly cross-linked at unsaturated sites in the monoglycerides and/or diglycerides.
1. A controlled release fertilizer composition comprising a particulate plant nutrient coated with a polyurethane coating of an isocyanate and at least one polyol, wherein the at least one polyol comprises monoglycerides and/or diglycerides that are cross-linked.
2. The controlled release fertilizer of claim 1 , wherein the at least one polyol is cross-linked with sulfur in an amount of up to about 25 wt. % based on the weight of the monoglycerides and/or diglycerides.
3. The controlled release fertilizer of claim 1 , wherein the polyurethane coating comprises the isocyanate, a wax, and the at least one polyol.
4. The controlled release fertilizer of claim 3 , wherein the wax comprises olefin wax, silicone wax, oxidized wax, natural wax, natural oil, fat, and partially and/or fully hydrogenated olefin wax, oil, or fat.
5. The controlled release fertilizer of claim 1 , wherein the monoglycerides and/or diglycerides comprise at least one monoglyceride of Formulas 1 or 2:
HO—CH2CH(OH)—CH2—X (Formula 1)
HO—CH2CH(X)—CH2—OH (Formula 2)
wherein X is —O—CO—C y H z , and wherein y ranges from 15-21 and z ranges from 29-41; and/or comprise at a least one diglyceride of Formulas 3 or 4:
HO—CH2-CH(X)—CH2—Y (Formula 3)
X—CH2-CH(OH)—CH2—Y (Formula 4)
wherein X and Y are the same or different, wherein X or Y are —O—CO—C n H m , and wherein n ranges from 15-21 and m ranges from 29-41.
6. The controlled release fertilizer of claim 5 , wherein y is 15-17 and z is 29-33.
7. The controlled release fertilizer of claim 1 , wherein the polyol comprises a catalytic reaction product of glycerol and triglycerides and/or diglycerides.
8. The controlled release fertilizer of claim 1 , wherein the polyol is a mixture of one or more monoglycerides and/or diglycerides formed by reacting a triglyceride and/or a diglyceride with any aliphatic, or aromatic, saturated, or unsaturated, natural, or synthetic, liquid, or solid, monofunctional, difunctional, trifunctional, or polyfunctional hydroxyl compound including, but not limited to: methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, propenol, propynol, butane diol, butenediol, butynediol, ethylene glycol, diethylene glycol, triethylene glycol, propanediol, dipropylene glycol, polyethylene glycol, polypropylene glycol, trimethylol propane, pentaerythritol, caprolactone polyols, carbonate polyols, ethanolamine, diethanolamine, triethanolamine, tetra (2-hydroxypropyl) ethylenediamine, sorbitol, and simple and/or complex sugars.
9. The controlled release fertilizer of claim 1 , wherein the polyol is cross-linked with a sulfur, oxygen and/or peroxide cross-linking moieties, or is cross-linked at unsaturated sites in the monoglycerides and/or diglycerides using heat, UV, or ionizing radiation.
10. The controlled release fertilizer of claim 1 , wherein the isocyanate comprises any one of a diphenylmethane diisocyanate and/or a toluene diisocyanate including any isomeric, oligomeric, monomeric, or polymeric forms thereof.
11. The controlled release fertilizer of claim 1 , wherein a ratio of NCO groups from the isocyanate to the hydroxyl groups in the polyol in the mixture is in the range of about 0.8 to about 3.0.
12. The controlled release fertilizer of claim 1 , wherein the plant nutrient comprises at least one nutrient from the nutrients listed below:
Nitrogen derivatives (as Nitrogen):
0 wt. %-45.54 wt. %
Phosphorus derivatives (as P 2 O 5 ):
0 wt. %-51.48 wt. %
Potassium derivatives (as K 2 O):
0 wt. %-61.38 wt. %
Iron Sulfate:
0 wt. %-99 wt. %
Iron EDTA chelate:
0 wt. %-99 wt. %
Copper Sulfate:
0 wt. %-99 wt. %
Manganese Sulfate:
0 wt. %-99 wt. %
Zinc Sulfate:
0 wt. %-99 wt. %
Sodium Molybdate:
0 wt. %-99 wt. %
Sodium Borate:
0 wt. %-99 wt. % and/or
Magnesium Sulfate:
0 wt. %-99 wt. %,
wherein the listed amounts of nutrients are weight percentages based on the weight of the controlled release fertilizer composition.
13. A controlled release fertilizer composition comprising a particulate plant nutrient coated with a coating of an isocyanate and at least one polyol comprising a mixture of glycerides, with the polyol having a monoglyceride content of at least 45 wt. %.