Gas generant composition

Abstract

Preferred gas generant compositions incorporate a combination of 5-aminotetrazole nitrate and an oxidizer. The oxidizer may be selected from a group including nonmetal and metal nitrates, nitrites, chlorates, chlorites, perchlorates, and oxides. 5-aminotetrazole nitrate is characterized as an oxygen-rich fuel and is therefore considered to be a self-deflagrating fuel. To tailor the oxygen balance in certain applications, however, the use of an oxidizer is preferred. Methods of formulating the compositions are also described. These compositions are especially suitable for inflating air bags and actuating seatbelt pretensioners in passenger-restraint devices.

1 . A gas generant composition formed from a method comprising the steps of: 
 adding a nitratable base fuel to an excess amount of nitric acid thereby forming a mixture;    adding at least one oxidizer to the mixture;    stirring the mixture to form a homogeneous wet paste;    forming the paste into a desired shape; and 
 drying the formed paste to form a solid solution consisting essentially of a fuel and an oxidizer wherein said fuel consists essentially of a nitrated nitratable base fuel, said nitratable base fuel selected from the group consisting of nitrourea, 5-aminotetrazole, diaminotriazole, urea, azodicarbonamide, hydrazodicarbonamide, semicarbazide, carbohydrazide, biuret, 3,5-diamino-1,2,4-triazole, dicyandiamide, and 3-amino-1,2,4-triazole.  
   
   
   
       2 . The composition of  claim 1  formed from the method further comprising the step of chilling the nitric acid to 0-20° C. prior to the addition of the nitratable base fuel.  
   
   
       3 . The composition of  claim 1  wherein at least one oxidizer is selected from the group consisting of nonmetal, alkali metal, and alkaline earth metal nitrates, nitrites, perchlorates, chlorates, and chlorites, and alkali, alkaline earth, and transitional metal oxides.  
   
   
       4 . The composition of  claim 3  wherein at least one oxidizer is selected from the group consisting of phase stabilized ammonium nitrate, ammonium nitrate, potassium nitrate, and strontium nitrate.  
   
   
       5 . The composition of  claim 1  wherein the excess nitric acid has a molarity of 15.9M or less.  
   
   
       6 . The composition of  claim 1  formed from the method further comprising forming the paste into granules, pellets, or cylindrical noodles.  
   
   
       7 . A gas generant composition formed from a method of formulating a gas generant composition comprising the steps of: 
 chilling a predetermined amount of nitric acid to 0-20 degrees Celsius;    adding 5-aminotetrazole to the chilled nitric acid to form a slurry, the nitric acid diluted by water and provided in at least a sufficient molarity and quantity to form 5-aminotetrazole nitrate;    adding ammonium nitrate and potassium nitrate to the slurry wherein potassium nitrate is about 10% by weight of the combined weight of the ammonium nitrate and the potassium nitrate;    stirring the slurry to form a wet paste, thereby forming a solid solution consisting essentially of a fuel and an oxidizer, the fuel consisting essentially of 5-aminotetrazole nitrate and the oxidizer containing phase stabilized ammonium nitrate, wherein the fuel is provided at about 25-95% and the oxidizer is provided at about 5-75%, the percentages stated by weight of the gas generant composition;    forming the paste into a desired shape; and    drying the formed paste to remove any residual nitric acid and/or water.    
   
   
       9 . A gas generant composition formed from a method comprising the steps of: 
 adding a nitratable base fuel to an excess amount of nitric acid thereby forming a mixture;    adding ammonium nitrate and a phase stabilizer to the slurry wherein said phase stabilizer and said ammonium nitrate coprecipitate to form phase stabilized ammonium nitrate;    stirring the mixture to form a homogeneous wet paste;    forming the paste into a desired shape; and    drying the formed paste to form a solid solution consisting essentially of a fuel and phase stabilized ammonium nitrate, wherein said fuel consists essentially of a nitrated nitratable base fuel, said nitratable base fuel selected from the group consisting of nitrourea, 5-aminotetrazole, diaminotriazole, urea, azodicarbonamide, hydrazodicarbonamide, semicarbazide, carbohydrazide, biuret, 3,5-diamino-1,2,4-triazole, dicyandiamide, and 3-amino-1,2,4-triazole.    
   
   
       10 . A gas generant composition formed from the method of  claim 9  wherein said phase stabilizer is a potassium salt selected from potassium nitrate and potassium perchlorate.