Methods for forming energetic molding powders and the energetic molding powders formed by these methods

Abstract

Methods for manufacturing explosives and the explosives manufactured by the methods are disclosed. Embodiments include mechanical mixing energetic particles with a thermoset binder material. Some embodiments include mixing the particles and binder using a bladeless mixer until homogeneous. Embodiments may also include heating a mixture of high energetic molding powder and a binder material at a low temperature (e.g., 70° C.) until the binder material is partially cured. Some embodiments include breaking up the mixture into pieces about 1 mm in size to form an energetic molding powder. And some embodiments include pressing a mixture of energetic molding powder into a die.

What is claimed is: 
     
         1 . A method of manufacturing an energetic molding powder, comprising:
 combining energetic particles with a binder material into a mixture;   partially curing the mixture of energetic particles and binder material by
 applying heat to the mixture of energetic particles and binder material, and 
 removing the applied heat from the mixture of energetic particles and binder material before the mixture of energetic particle and binder mixture is fully cured; and 
   breaking up the partially cured energetic particle and binder mixture into smaller pieces.   
     
     
         2 . The method of  claim 1 , further comprising:
 after said partially curing, mixing the partially cured mixture of energetic particles and binder material.   
     
     
         3 . The method of  claim 1 , further comprising:
 stopping said breaking up the partially cured energetic particle and binder mixture into smaller pieces when no piece has a largest dimension larger than 1 centimeter.   
     
     
         4 . The method of  claim 1 , further comprising:
 placing the partially cured energetic particle and binder mixture into a die form;   pressing the partially cured energetic particle and binder mixture in the die form; and   removing the pressed energetic particle and binder mixture from the die form.   
     
     
         5 . The method of  claim 4 , further comprising:
 after said pressing, slowly releasing the pressure on the energetic molding powder over a predetermined time.   
     
     
         6 . The method of  claim 1 , wherein the binder is a photopolymer binder. 
     
     
         7 . The method of  claim 1 , wherein the binder is a thermoset binder. 
     
     
         8 . The method of  claim 1 , wherein:
 the energetic particles are high melting explosive (HMX) or Royal demolition explosive (RDX); and   the binder material is a hydroxyl-terminated polybutadiene (HTPB) binder.   
     
     
         9 . The method of  claim 8 , wherein the energetic particles and a thermoset binder material being mixed are
 90 wt. % solids loading of energetic particles and a coarse (150-212 μm) to fine (90-150 μm) ratio of 4:1,   10 wt. % of binder including   6.56 wt. % HTPB,   1.95 wt. % dimeryl diisocyanate (DDI), and   1.5 wt. % isodecyl pelargonate plasticizer (IDP).   
     
     
         10 . The method of  claim 9 , wherein said mixing includes:
 scraping the mixture of energetic particles and thermoset binder material that has adhered to the side of the bladeless mixer from the side of the bladeless mixer;   stirring the mixture of the energetic particles and the thermoset binder material; and   repeating said rotating, scraping and stirring until the mixture of energetic particles and thermoset binder material is homogeneous.   
     
     
         11 . The method of  claim 10 , wherein:
 said heating includes placing the mixture of energetic particles and thermoset binder material in an oven heated to 70° C. for 8 hours.   
     
     
         12 . The method of  claim 11 , wherein:
 said pressing includes pressing the partially cured energetic molding powder at 250 MPa for 10 minutes.   
     
     
         13 . The method of  claim 1 , further comprising:
 after said partially curing, mixing the partially cured mixture of energetic particles and binder material, said mixing including
 scraping the mixture of energetic particles and thermoset binder material that has adhered to the side of the bladeless mixer from the side of the bladeless mixer, 
 stirring the mixture of the energetic particles and the thermoset binder material, and 
 repeating said rotating, scraping and stirring until the mixture of energetic particles and thermoset binder material is homogeneous; 
   stopping said breaking up the partially cured energetic particle and binder mixture into smaller pieces when no piece has a largest dimension larger than 1 centimeter;   placing the partially cured energetic particle and binder mixture into a die form;   pressing the partially cured energetic particle and binder mixture in the die form;   slowly releasing the pressure on the energetic molding powder over a predetermined time; and   removing the pressed energetic particle and binder mixture from the die form.   
     
     
         14 . An energetic molding powder, comprising:
 a mixture of energetic particles and a binder material, wherein said mixture of energetic particles and a binder material is formed by
 combining energetic particles with a binder material into a mixture; 
   partially curing the mixture of energetic particles and binder material by
  applying heat to the mixture of energetic particles and binder material, and 
  removing the applied heat from the mixture of energetic particles and binder material before the mixture of energetic particle and binder mixture is fully cured; and 
 breaking up the partially cured energetic particle and binder mixture into smaller pieces. 
   
     
     
         15 . The energetic molding powder of  claim 14 , wherein said mixture of energetic particles and a binder material is further formed by
 after said partially curing, mixing the partially cured mixture of energetic particles and binder material, said mixing including
 scraping the mixture of energetic particles and thermoset binder material that has adhered to the side of the bladeless mixer from the side of the bladeless mixer, 
 stirring the mixture of the energetic particles and the thermoset binder material, and 
 repeating said rotating, scraping and stirring until the mixture of energetic particles and thermoset binder material is homogeneous; 
   stopping said breaking up the partially cured energetic particle and binder mixture into smaller pieces when no piece has a largest dimension larger than 1 centimeter;   placing the partially cured energetic particle and binder mixture into a die form;   pressing the partially cured energetic particle and binder mixture in the die form;   slowly releasing the pressure on the energetic molding powder over a predetermined time; and   removing the pressed energetic particle and binder mixture from the die form.   
     
     
         16 . The energetic molding powder of  claim 14 , wherein:
 the energetic particles are high melting explosive (HMX) or Royal demolition explosive (RDX); and   the binder material is a hydroxyl-terminated polybutadiene (HTPB) binder.   
     
     
         17 . The energetic molding powder of  claim 16 , wherein the energetic particles and a thermoset binder material are
 90 wt. % solids loading of energetic particles and a coarse (150-212 μm) to fine (90-150 μm) ratio of 4:1,   10 wt. % of binder including   6.56 wt. % HTPB,   1.95 wt. % dimeryl diisocyanate (DDI), and   1.5 wt. % isodecyl pelargonate plasticizer (IDP).   
     
     
         18 . The energetic molding powder of  claim 14 , wherein the heating includes placing the mixture of energetic particles and thermoset binder material in an oven heated to 70° C. for 8 hours. 
     
     
         19 . The energetic molding powder of  claim 14 , wherein said the pressing includes pressing the partially cured energetic molding powder at 250 MPa for 10 minutes.