Porous igniter coating for use in automotive airbag inflators

Abstract

An ignition composition effective to form a porous igniter substance capable of adhering to an associated inflator apparatus surface for use in an automotive inflatable restraint system and a method for preparing a porous igniter coating formed from the ignition composition are provided. The ignition composition includes a fuel, an oxidizer, a polymeric binder and a blowing agent effective, upon decomposition, to increase the surface area of the porous igniter substance. The porous igniter substance or coating is formed by heating the ignition composition to a predetermined temperature.

What is claimed is:  
     
         1 . An ignition composition effective to form an igniter substance having a surface area, the ignition composition including a fuel and an oxidizer and further comprising: 
 a polymeric binder; and    a blowing agent effective, upon decomposition, to increase the surface area of the igniter substance;    wherein the ignition composition, upon being heated to a predetermined temperature, forms an igniter substance which is porous and capable of adhering to an associated inflator apparatus surface.    
     
     
         2 . The ignition composition of  claim 1 , wherein the fuel comprises a powdered metal.  
     
     
         3 . The ignition composition of  claim 1 , wherein the fuel is selected from the group consisting of aluminum, magnesium, alloys of aluminum and magnesium, and combinations thereof.  
     
     
         4 . The ignition composition of  claim 1 , wherein the fuel comprises an alloy of aluminum and magnesium.  
     
     
         5 . The ignition composition of  claim 1 , wherein the fuel comprises a metalloid.  
     
     
         6 . The ignition composition of  claim 1 , wherein the fuel comprises boron.  
     
     
         7 . The ignition composition of  claim 1 , wherein the fuel comprises a gas producing organic compound.  
     
     
         8 . The ignition composition of  claim 1 , wherein the fuel comprises guanidine nitrate.  
     
     
         9 . The ignition composition of  claim 1 , wherein the polymeric binder is selected from the group consisting of modified cellulose polymers, acrylate polymers, acrylamide polymers, and combinations thereof.  
     
     
         10 . The ignition composition of  claim 1 , wherein the polymeric binder comprises a modified cellulose polymer including hydroxypropyl cellulose.  
     
     
         11 . The ignition composition of  claim 1 , wherein the blowing agent is selected from the group consisting of aminoguanidine bicarbonate, ammonium oxalate, azodicarbonamide, ammonium carbonate, ammonium carbamate, ammonium bicarbonate, 4,4′-oxydibenzene sulfonyl hydrazide, and combinations thereof.  
     
     
         12 . The ignition composition of  claim 1 , wherein the blowing agent comprises aminoguanidine bicarbonate.  
     
     
         13 . The ignition composition of  claim 1 , wherein the ignition composition upon being heated to a temperature of between about 130° C. and about 170° C. forms the porous igniter substance.  
     
     
         14 . The ignition composition of  claim 1 , wherein the associated surface is selected from the group consisting of at least a portion of a surface of a gas generant wafer or tablet, at least a portion of an interior surface of an inflator device, at least a portion of a surface of an electrical squib, at least a portion of a surface of a damper pad, and combinations thereof.  
     
     
         15 . A gas generant material for use in an automotive safety restraint system comprising: 
 the ignition composition of  claim 1  applied to at least a portion of a surface of the gas generant material;    wherein the ignition composition, upon being heated to a predetermined temperature, forms a porous igniter coating that adheres to at least a portion of the surface of the gas generant material.    
     
     
         16 . A hybrid gas storage container for use in an automotive safety restraint system comprising: 
 the ignition composition of  claim 1  applied to an inner surface of the hybrid gas storage container;    wherein the ignition composition, upon being heated to a predetermined temperature, forms a porous igniter coating that adheres to the inner surface of the hybrid gas storage container.    
     
     
         17 . A damper pad for use in an automotive safety restraint system comprising: 
 the ignition composition of  claim 1  applied to at least a portion of a surface thereof;    wherein the ignition composition, upon being heated to a predetermined temperature, forms a porous igniter coating that adheres to at least a portion of the surface of the damper pad.    
     
     
         18 . An ignition composition effective to form an igniter substance having a surface area, the ignition composition comprising: 
 about 15 to about 50 composition weight percent of a fuel;    about 50 to about 85 composition weight percent of an oxidizer;    about 1 to about 20 composition weight percent of a polymeric binder; and    about 1 to about 20 composition weight percent of a blowing agent effective, upon decomposition, to increase the surface area of the igniter substance;    wherein the ignition composition, upon being heated to a predetermined temperature, forms an igniter substance which is porous and capable of adhering to an associated inflator apparatus surface.    
     
     
         19 . The ignition composition of  claim 18 , wherein the fuel is selected from the group consisting of metal fuels, metalloid fuels, gas generating organic fuels, and combinations thereof.  
     
     
         20 . The ignition composition fo  claim 18 , wherein the fuel comprises a metal fuel selected from the group consisting of aluminum, magnesium, alloys of aluminum and magnesium, and combinations thereof.  
     
     
         21 . The ignition composition of  claim 18 , wherein the fuel comprises an alloy of aluminum and magnesium.  
     
     
         22 . The ignition composition of  claim 21 , wherein the fuel further comprises boron.  
     
     
         23 . The ignition composition of  claim 18 , wherein the oxidizer is potassium nitrate.  
     
     
         24 . The ignition composition of  claim 18 , wherein the polymeric binder is hydroxypropyl cellulose.  
     
     
         25 . The ignition composition of  claim 18 , wherein the polymeric binder is an aqueous emulsion of polyacrylate polymers.  
     
     
         26 . The ignition composition of  claim 18 , wherein the blowing agent is aminoguanidine bicarbonate.  
     
     
         27 . The ignition composition of  claim 18 , further comprising a desensitizing agent.  
     
     
         28 . The ignition composition of  claim 26 , wherein the ignition composition comprises a desensitizing agent in an amount of up to about 10 composition weight percent.  
     
     
         29 . The ignition composition of  claim 27 , wherein the desensitizing agent is bentonite clay.