Controlled release pesticidal composition and method of making

Abstract

A granular controlled-release pesticide comprising “core” granules such as ammonium sulfate, an inner polymer membrane formed in situ on said granules of ammonium sulfate, an acephate pesticide applied to the inner polymer membrane on the core granules, and an outer controlled-release polyurethane membrane formed in situ on said pesticide to permit controlled release of the pesticide.

It is claimed:  
     
         1 . A granular pesticide comprising a core material coated with an inner polymer membrane formed in situ on the core material, a pesticide applied to the inner polymer membrane on the core material, and an outer controlled release polymer membrane formed in situ on the pesticide to permit controlled release of the pesticide.  
     
     
         2 . The granular pesticide of  claim 1  wherein the core material is ammonium sulfate.  
     
     
         3 . The granular pesticide of claims  1  or  2  wherein the pesticide is acephate.  
     
     
         4 . The granular pesticide of claims  1  or  2  or  3  wherein the inner polymer membrane is formed in situ from a diisocyanate and a polyol.  
     
     
         5 . The granular pesticide of  claim 4  wherein the diisocyanate is polymeric diphenylmethane diisocyanate.  
     
     
         6 . The granular pesticide of claims  4  or  5  wherein the polyol is a polyester polyol.  
     
     
         7 . The granular pesticide of  claim 6  wherein the polyester polyol is blended with triethanolamine.  
     
     
         8 . The granular pesticide of claims  1  or  2  or  3  or  4  wherein the outer controlled release polymer membrane is formed in situ from a diisocyanate and a polyol.  
     
     
         9 . The granular pesticide of  claim 8  wherein the diisocyanate is polymeric diphenylmethane diisocyanate.  
     
     
         10 . The granular pesticide of  claim 8  or  9  wherein the polyol is a polyester polyol.  
     
     
         11 . The granular pesticide of  claim 10  wherein the polyester polyol is blended with triethanolamine.  
     
     
         12 . The granular pesticide of  claim 7  wherein said granular pesticide is coated with a plurality of layers of pesticide.  
     
     
         13 . A method of making a granular pesticide comprising the steps of 
 coating a core material with an inner polymer membrane formed in situ on the core material;    applying a pesticide to the inner polymer membrane on the core material, and    forming in situ an outer controlled release membrane on the pesticide to permit controlled release of the pesticide.    
     
     
         14 . The method of  claim 13  wherein the core material is ammonium sulfate.  
     
     
         15 . The method of claims  13  or  14  wherein the pesticide is acephate.  
     
     
         16 . The method of claims  13  or  14  or  15  wherein the inner polymer membrane is formed in situ from a diisocyanate and a polyol.  
     
     
         17 . The method of  claim 16  wherein the polyol is a polyester polyol.  
     
     
         18 . The method of  claim 17  wherein the polyester polyol is blended with triethanolamine.  
     
     
         19 . The method of claims  13  or  14  or  15  or  16  wherein the outer controlled release polymer membrane is formed in situ from a diisocyanate and a polyol.  
     
     
         20 . The method of  claim 19  wherein the diisocyanate is polymeric diphenylmethane diisocyanate.  
     
     
         21 . The method of claims  19  or  20  wherein the polyol is a polyester polyol.  
     
     
         22 . The method of  claim 21  wherein the polyester polyol is blended with triethanolamine.  
     
     
         23 . The method of  claim 22  wherein said granular pesticide is coated with a plurality of layers of pesticide.