Non-ammonium nitrate based generants

Abstract

This disclosure is directed to an airbag gas generant formulation optimized for hybrid airbag inflators, and an airbag inflator, an airbag, an airbag module comprising same, and a method of inflating an airbag using the airbag gas generant.

1 . An airbag gas generant formulation optimized for hybrid airbag inflators, the formulation comprising:
 40 wt % to 50 wt % strontium nitrate;   35 wt % to 45 wt % nitroguanidine;   3 wt % to 7 wt % potassium perchlorate;   3 wt % to 6 wt % w/w polyvinyl alcohol; and   2 wt % to 6 wt % w/w strontium oxalate.   
     
     
         2 . The airbag gas generant formulation of  claim 1  which has at least one property selected from the group consisting of:
 a gas yield of greater than 1.57 grams of per cubic centimeter (g/cc); 
 a constant volume flame temperature of 2700° K to 2800° K; and 
 an overall oxygen balance of the formulation −2% to +2%. 
 
     
     
         3 . The airbag gas generant formulation of  claim 1 , wherein the formulation comprises
 48.2 wt % strontium nitrate;   36.8 wt % nitroguanidine;   5 wt % potassium perchlorate;   5 wt % strontium oxalate; and   5 wt % polyvinyl alcohol.   
     
     
         4 . The airbag gas generant formulation of  claim 1 , wherein the formulation further comprises
 1 wt % to 5 wt % cupric oxide as a burning rate modifier.   
     
     
         5 . The airbag gas generant formulation of  claim 4  wherein the formulation is
 44.1 wt % strontium nitrate; 
 39.9 wt % nitroguanidine; 
 5 wt % potassium perchlorate; 
 4 wt % strontium oxalate; 
 4 wt % polyvinyl alcohol; and 
 3 wt % cupric oxide. 
 
     
     
         6 . The airbag gas generant formulation of  claim 1  which further comprises
 2 wt % to 6 wt % Kaolin for slag formation and as a coolant. 
 
     
     
         7 . The airbag gas generant formulation of  claim 1  which further comprises
 2 wt % to 6 wt % aluminum oxide for slag formation and as a coolant. 
 
     
     
         8 . The airbag gas generant formulation of  claim 1  which further comprises
 2 wt % to 6 wt % silicon dioxide for slag formation and as a coolant. 
 
     
     
         9 . The airbag gas generant formulation of  claim 1  which further comprises 2 wt % to 6% wt % of at least one selected from the group consisting of:
 kaolin; 
 aluminum oxide; and 
 silicon dioxide. 
 
     
     
         10 . The airbag gas generant formulation of  claim 1  which does not contain oxygen as a stored gas. 
     
     
         11 . An inflator for an airbag comprising the airbag gas generant formulation of  claim 1  wherein the inflator does not contain oxygen as a stored gas. 
     
     
         12 . A method for inflating an airbag comprising the steps of
 igniting the airbag gas generant formulation of  claim 1  to generate a gas; and   inflating the airbag with the gas.   
     
     
         13 . The method of  claim 12  wherein the igniting step does not involve igniting oxygen as a stored gas.