Gas Generant Manufacturing Method

Abstract

A method of forming a gas generating composition containing a salt of dinitrosalicylic acid and ammonium nitrate or phase stabilized ammonium nitrate. The method involves the co-precipitation of a salt of 3,5-dinitrosalicylic acid with phase stabilized ammonium nitrate. A gas generating composition 12 is also presented along with a gas generator 10 containing the gas generating composition 12 . The gas generator 10 may be contained within a gas generating system 200 such as an airbag inflator 10 or seat belt assembly 150 , or more broadly within a vehicle occupant protection system 180.

What is claimed is: 
     
         1 . A method of forming a gas generating composition comprising the following steps:
 providing a solvent within a jacketed mixing vessel;   adding a stoichiometric amount of dinitrosalicylic acid to the solvent and stirring;   adding at least one oxidizer in a stoichiometric amount to the solution and stifling, the oxidizer selected from ammonium nitrate and phase stabilized ammonium nitrate; and   adding a precipitating agent to the composition and continuing to stir, thereby forming solids.   
     
     
         2 . The method of  claim 1  wherein the solvent is selected from water, ethanol, methanol, propanol, and any other solvent miscible with water. 
     
     
         3 . The method of  claim 1  wherein the precipitating agent is a potassium source and is added when ammonium nitrate is added to the vessel. 
     
     
         4 . The method of  claim 3  wherein the precipitating agent is selected from potassium nitrate, potassium hydroxide, and dipotassium carbonate. 
     
     
         5 . The method of  claim 1  wherein the precipitating agent is an ammonium source and is added when phase stabilized ammonium nitrate is added to the vessel. 
     
     
         6 . The method of  claim 5  wherein the precipitating agent is selected from ammonium hydroxide and ammonium carbonate. 
     
     
         7 . The method of  claim 1  further comprising the step of adding a secondary fuel to the vessel and continuing to stir. 
     
     
         8 . The method of  claim 7  wherein diammonium salt of 5,5′-bis-1H-tetrazole is added as a secondary fuel. 
     
     
         9 . The method of  claim 7  wherein the secondary fuel that is added to the vessel is selected from tetrazoles and salts thereof; triazoles and salts thereof; azoles and salts thereof; guanidine salts and derivatives; imides; amides; aliphatic carboxylic acids and salts thereof; aromatic carboxylic acids and salts thereof; nitro-aromatic carboxylic acids and salts thereof; nitrosalicylic acids and salts thereof; amines; nitrophenols; pyrazoles;
 imidazoles; azines; and mixtures thereof. 
 
     
     
         10 . The method of  claim 1  further comprising the step of adding additional solvent after adding the oxidizer to enhance the solubility of the constituents that are added to the vessel, while continuing to heat and stir the solution. 
     
     
         11 . The method of  claim 1  further comprising the step of forming the solid precipitate into a desired form. 
     
     
         12 . The method of  claim 11  wherein the method is selected from compression and extrusion methods. 
     
     
         13 . A composition formed from the method of  claim 1 . 
     
     
         14 . A composition formed from the method of  claim 7 . 
     
     
         15 . A composition formed from the method of  claim 8 . 
     
     
         16 . A composition formed from the method of  claim 9 . 
     
     
         17 . A gas generator containing a composition formed from the method of  claim 1 . 
     
     
         18 . A vehicle occupant protection system containing a composition formed from the method of  claim 1 . 
     
     
         19 . The method of  claim 1  further comprising the step of heating and maintain the temperature of the solution to about 100 C-110 C. 
     
     
         20 . The method of  claim 1  further comprising the step of stirring and heating the solids until the desired dryness within the resultant solids is attained.