Granular controlled release agrochemical compositions and process for the preparation thereof

Abstract

A granular agrochemical composition is disclosed including a granular core material having a water soluble portion with a first coating layer applied on the surface of the core material and a second coating layer applied on the surface of the first coating layer. The first coating layer includes a wax composition having a biologically active ingredient incorporated therein and the second coating layer includes a polymeric composition. The granular agrochemical composition exhibits a controlled rate of release of the biologically active ingredient therefrom over a period greater than about 30 days from the date of initial exposure of the granular composition to moisture whereby essentially all of the biologically active ingredient incorporated in the wax material of the first coating layer is released from the granular composition before the water soluble portion of the granular core material is released from the granular composition.

1 . A granular agrochemical composition comprising: 
 a) a granular core material including a water soluble portion;    b) a first coating layer comprising a wax composition having a biologically active ingredient incorporated therein applied on the surface of the core material; and    c) a second coating layer comprising a polymeric composition applied on the surface of the first coating layer;    d) said granular composition exhibiting a controlled rate of release of the biologically active ingredient therefrom over a period greater than about 30 days from the date of initial exposure of the granular composition to moisture whereby essentially all of the biologically active ingredient incorporated in the wax material of the first coating layer is released from the granular composition before the water soluble portion of the granular core material is released from the granular composition.    
   
   
       2 . The granular agrochemical composition of  claim 1  wherein the water soluble portion of the core material generates sufficient osmotic pressure within the granular composition to cause the biologically active ingredient in the first coating layer to be released therefrom when the composition is contacted with moisture.  
   
   
       3 . The granular agrochemical composition of  claim 2  wherein the second coating layer is structured to withstand the osmotic pressure generated by the core material.  
   
   
       4 . The granular agrochemical composition of  claim 1  wherein the water soluble core material is a fertilizer.  
   
   
       5 . The granular agrochemical composition of  claim 4  wherein the fertilizer is selected from the group consisting of ammonium sulfate, potassium nitrate, potassium sulfate, urea, ammonium nitrate, monopotassium sulfate, ammonium phosphate, super-phosphate, calcium phosphates, potassium phosphate, potassium chloride, magnesium oxide, magnesium sulfate, dolomite and mixture thereof.  
   
   
       6 . The granular agrochemical composition of  claim 4  wherein the core material includes at least one secondary nutrient or micronutrient.  
   
   
       7 . The granular agrochemical composition of  claim 6  wherein the secondary nutrient is selected from the group consisting of calcium, magnesium, sulfur and mixtures thereof.  
   
   
       8 . The granular agrochemical composition of  claim 6  wherein the micronutrient is selected from the group consisting of chelated or non-chelated iron, copper, zinc, manganese, boron, cobalt, chlorine, sodium, molybdenum and mixtures thereof.  
   
   
       9 . The granular agrochemical composition of  claim 1  wherein the core material includes a non-active material.  
   
   
       10 . The granular agrochemical composition of  claim 1  wherein the core material has a solubility of about 2 to about 800 g/l.  
   
   
       11 . The granular agrochemical composition of  claim 1  wherein the core material is shaped as a granule having a diameter of about 0.35 to about 6 mm.  
   
   
       12 . The granular agrochemical composition of  claim 1  wherein the biologically active ingredient is selected from the group consisting of pesticides, insecticides, herbicides, fungicides, fertilizers, growth regulators, pheromones, biostimulants, acaricides, miticides, nematocides and mixtures thereof.  
   
   
       13 . The granular agrochemical composition of  claim 1  wherein the wax composition has a melting point of greater than 50° C.  
   
   
       14 . The granular agrochemical composition of  claim 13  wherein the wax composition is hydrophobic.  
   
   
       15 . The granular agrochemical composition of  claim 13  wherein the wax composition is hydrophilic.  
   
   
       16 . The granular agrochemical composition of  claim 1  wherein the wax composition is water soluble.  
   
   
       17 . The granular agrochemical composition of  claim 1  wherein the polymeric composition is a (semi-)water permeable material selected from the group consisting of thermosetting resins, thermoplastic resins, latex polymers and mixtures thereof.  
   
   
       18 . The granular agrochemical composition of  claim 1  wherein greater than about 90% of the biologically active ingredient incorporated in the wax composition of the first layer is released from the granular composition while a residual amount of the water soluble portion of the core material remains in the granular composition.  
   
   
       19 . A process for preparing a granular agrochemical composition exhibiting a controlled rate of release of a biologically active ingredient incorporated in the granular composition over a period greater than about 30 days from the date of initial exposure of the granular composition to moisture whereby essentially all of the biologically active ingredient is released from the granular composition while at least a residual amount of a core material remains in the granular composition comprising: 
 a) providing a granular core material;    b) applying a first coating layer comprising a wax composition having a biologically active ingredient incorporated therein on the surface of the core material; and    c) applying a second coating layer comprising a polymeric composition on the surface of the first coating layer.    
   
   
       20 . The process of  claim 19  wherein the core material is at least partially water soluble whereby a sufficient osmotic pressure is generated within the granular composition to cause the biologically active ingredient in the first coating to be released therefrom when the core material is contacted with water.  
   
   
       21 . The process of  claim 20  wherein the second coating layer is structured to withstand the osmotic pressure generated by the core material.  
   
   
       22 . The process of  claim 20  wherein the water soluble core material is a fertilizer.  
   
   
       23 . The process of  claim 22  wherein the fertilizer is selected from the group consisting of ammonium sulfate, potassium nitrate, potassium sulfate, urea, ammonium nitrate, monopotassium sulfate, ammonium phosphate, super-phosphate, calcium phosphates, potassium phosphate, potassium chloride, magnesium oxide, magnesium sulfate, dolomite and mixture thereof.  
   
   
       24 . The process of  claim 22  wherein the core material includes at least one secondary nutrient or micronutrient.  
   
   
       25 . The process of  claim 24  wherein the secondary nutrient is selected from the group consisting of calcium, magnesium, sulfur and mixtures thereof.  
   
   
       26 . The process of  claim 25  wherein the micronutrient is selected from the group consisting of chelated or non-chelated iron, copper, zinc, manganese, boron, cobalt, chlorine, sodium, molybdenum and mixtures thereof.  
   
   
       27 . The process of  claim 19  wherein the core material includes a non-active material.  
   
   
       28 . The process of  claim 19  wherein the core material has a solubility of about 2 to about 800 g/l.  
   
   
       29 . The process of  claim 19  wherein the core material is shaped as a granule having a diameter of about 0.35 to about 6 mm.  
   
   
       30 . The process of  claim 19  wherein the biologically active ingredient is selected from the group consisting of pesticides, insecticides, herbicides, fungicides, fertilizers, growth regulators, pheromones, biostimulants, acaricides, miticides, nematocides and mixtures thereof.  
   
   
       31 . The process of  claim 19  wherein the wax composition has a melting point of greater than 50° C.  
   
   
       32 . The process of  claim 31  wherein the wax composition is hydrophobic.  
   
   
       33 . The process of  claim 31  wherein the wax composition is hydrophilic.  
   
   
       34 . The process of  claim 19  wherein the wax composition is water soluble.  
   
   
       35 . The process of  claim 19  wherein the polymeric composition is a (semi-)water permeable material selected from the group consisting of thermosetting resins, thermoplastic resins, latex polymers and mixtures thereof.  
   
   
       36 . The process of  claim 19  wherein greater than about 90% of the biologically active ingredient incorporated in the wax composition of the first layer is released from the granular composition while a residual amount of the core material remains in the granular composition.  
   
   
       37 . An agrochemical composition which exhibits controlled release of a biologically active ingredient over a period greater than about 30 days from the date of initial exposure of the composition to moisture at a release rate such that essentially all of the biologically active ingredient is released from the composition while at least a residual amount of a water soluble portion of a core material remains in the granular composition, the composition comprising a granular core material having a first coating layer comprising a wax material having a plant protection product incorporated therein applied on the core material and a second polymeric coating layer applied over the first coating layer.  
   
   
       38 . The granular agrochemical composition of  claim 37  wherein the core material is at least partially water soluble whereby a sufficient osmotic pressure is generated within the granular composition to cause the biologically active ingredient in the first coating to be released therefrom when the agrochemical composition is contacted with water.  
   
   
       39 . The granular agrochemical composition of  claim 37  wherein the second coating layer is structured to withstand the osmotic pressure generated by the core material.  
   
   
       40 . The granular agrochemical composition of  claim 37  wherein the water soluble portion of the core material is a fertilizer.  
   
   
       41 . The granular agrochemical composition of  claim 37  wherein the biologically active ingredient is selected from the group consisting of pesticides, insecticides, herbicides, fungicides, fertilizers, growth regulators, pheromones, biostimulants, acaricides, miticides, nematocides and mixtures thereof.  
   
   
       42 . The granular agrochemical composition of  claim 37  wherein the wax composition has a melting point of greater than 50° C.  
   
   
       43 . The granular agrochemical composition of  claim 42  wherein the wax composition is hydrophobic.  
   
   
       44 . The granular agrochemical composition of  claim 42  wherein the wax composition is hydrophilic.  
   
   
       45 . The granular agrochemical composition of  claim 37  wherein the polymeric composition is a (semi-)water permeable material selected from the group consisting of thermosetting resins, thermoplastic resins, latex polymers and mixtures thereof.  
   
   
       46 . The granular agrochemical composition of  claim 37  wherein greater than about 90% of the biologically active ingredient incorporated in the wax composition of the first layer is released from the granular composition while a residual amount of the core material remains in the granular composition.