Moisture Barrier Coatings

A controlled release fertilizer comprising a water soluble nutrient core coated with one or more moisture barrier coatings, at least one of said moisture barrier coatings comprising:

• a. at least one organic wax;
• b. at least one polymer soluble in the wax;
• c. a thermoset polymer;
• wherein the weight ratio of organic wax to wax soluble polymer is from about 50:50 to about 98:2 and wherein the weight ratio of thermoset polymer to combined organic wax and wax soluble polymer is from about 50:50 to about 98:2, and wherein the organic wax and wax soluble polymer are mixed and dispersed into at least one component of the thermoset polymer before the thermoset polymer is applied to the surface and cured, the coating comprising a semi-interpenetrating network of the wax, the wax soluble polymer, and the thermoset polymer.

A method of producing a controlled release fertilizer comprising the steps of:

• i. providing a quantity of fertilizer particles;
• ii. heating the fertilizer particles to a temperature above the melting point of the organic wax;
• iii. providing one or more moisture barrier coatings, at least one of said moisture barrier coatings comprising:
• a. at least one organic wax
• b. at least one wax soluble polymer
• c. a thermoset polymer
• wherein the weight ratio of organic wax to wax soluble polymer is from about 50:50 to about 98:2 and wherein the weight ratio of thermoset polymer to combined organic wax and wax soluble polymer is from about 50:50 to about 98:2;
• iv. mixing the organic wax and wax soluble polymer to provide a mixture
• v. dispersing the mixture into at least one component of the thermoset polymer to provide a dispersion;
• vi. applying the dispersion to the fertilizer particles while providing mixing sufficient to spread the dispersion as a coating on the fertilizer particles, and
• vii. curing the thermoset polymer on the surface of the particles to form free flowing coated granules.