Gas generating system

Abstract

The present invention generally relates to gas generant compositions for inflators of occupant restraint systems, for example. A gas generating composition 12 formed in accordance with the present invention includes an alkyl cellulosic fuel/binder, an oxidizer, and a burn inhibitor or ignition catalyst. A vehicle occupant protection system 180 , and other gas generating systems, incorporate the compositions of the present invention.

1 . A gas generating system comprising a gas generating composition, said composition comprising: 
 a fuel/binder selected from the group consisting of cellulosic binders containing alkyl substitutions;    an oxidizer; and    an additive selected from dibutylthalates, dicyclohexourea, triacetin, molybdenum trioxide, molybdic acid, ammonium molybdate, sodium molybdate, phosphomolybdic acid, molybdenum disulfide, and sodium phosphomolybdate,    said additive provided at about 0.05 to 20 percent by weight of the composition.    
   
   
       2 . The gas generating system of  claim 1  further comprising a second additive selected from metal oxides and sulfates, said second additive provided at about 0.1 to 20% by weight of the composition.  
   
   
       3 . The gas generating system of  claim 2  wherein said second additive is selected from manganese oxide, cupric oxide, and ammonium sulfate.  
   
   
       4 . The gas generating system of  claim 1  wherein said oxidizer is selected from metallic and nonmetallic oxidizers, said oxidizer selected from nitrates, nitrites, perchlorates, chlorates, oxides, and basic metal nitrates.  
   
   
       5 . The gas generating system of  claim 4  wherein said oxidizer is selected from ammonium nitrate, phase stabilized ammonium nitrate stabilized, potassium nitrate, and strontium nitrate; nitrite salts such as potassium nitrite; chlorate salts such as potassium chlorate; perchlorate salts such as ammonium perchlorate and potassium perchlorate; oxides such as iron oxide and copper oxide; basic nitrate salts such as basic copper nitrate and basic iron nitrate; and mixtures thereof, said oxidizer provided at about 0.1-70% by weight.  
   
   
       6 . The gas generating system of  claim 1  further comprising a secondary fuel selected from azoles, nonmetal and metal salts of azoles, nitramine derivatives and salts of azoles, guanidines, guanidine derivatives, and salts of guanidines, azoamides, nitrate salts of azoamides, and mixtures thereof, said secondary fuel provided at about 0.1-50% by weight.  
   
   
       7 . The gas generating system of  claim 6  wherein: said azoles are selected from 5-aminotetrazole; said nonmetal salts of azoles are selected from monoammonium or diammonium salts of 5,5′-bis′1H-tetrazole, and 5-aminotetrazole nitrate; said nitramine derivatives and salts of azoles are selected from 5-nitraminotetrazole, dipotassium 5-nitraminotetrazole, monoammonium 5-nitraminotetrazole, and diammonium 5-nitraminotetrazole; said guanidines, guanidine derivatives, and salts of guanidines are selected from dicyandiamide, nitroguanidine, and guanidine nitrate; and said azoamides and nitrate salts of azoamides are selected from azodicarbonamide and azodicarbonamidine dinitrate.  
   
   
       8 . The gas generating system of  claim 1  wherein said cellulosic binders containing alkyl substitutions are selected from cellulosic binders containing alkyl substitutions selected from acetyl, propionyl, butyryl groups with hydroxyl groups.  
   
   
       9 . The gas generating system of  claim 1  wherein said cellulosic binder is selected from cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, hydroxyethylcellulose, hydrocypropyl cellulose, methyl cellulose, and ethyl hydroxyethyl cellulose.  
   
   
       10 . The gas generating system of  claim 1  further comprising a metal oxide at about 0.1-20% by weight of the gas generant composition.  
   
   
       11 . A vehicle occupant protection system containing the gas generating system of  claim 1 .  
   
   
       12 . A gas generant composition comprising: 
 a fuel/binder selected from the group consisting of cellulosic binders containing alkyl substitutions;    an oxidizer; and    an additive selected from dibutylthalates, dicyclohexourea, triacetin, molybdenum trioxide, molybdic acid, ammonium molybdate, sodium molybdate, phosphomolybdic acid, molybdenum disulfide, and sodium phosphomolybdate,    said additive provided at about 0.05 to 20 percent by weight of the composition.