Foamed igniter for use in automotive airbag inflators

Abstract

A foamable igniter composition effective to form a foamed igniter substance for use in an inflator device of an inflatable restraint system and a method for preparing a foamed igniter substance formed from the foamable igniter composition are provided. The foamable igniter composition includes a fluoropolymer binder oxidant, a plasticizer effective to render the fluoropolymer binder oxidant flexible, a metal fuel that is reactive with the fluoropolymer binder oxidant, a blowing agent effective to render the foamable igniter composition porous, and a crosslinking agent effective to structurally stabilize the foamed igniter substance. The foamed igniter substance is formed by heating the foamable igniter composition to a predetermined temperature. The consistency of the foamable igniter composition may be adjusted to allow the composition to be sprayed, extruded or molded as desired.

1 . A foamable igniter composition effective to form a foamed igniter substance, the foamable igniter composition comprising: 
 a fluoropolymer binder oxidant;    a plasticizer effective to render the fluoropolymer binder oxidant flexible;    a metal fuel which is reactive with the fluoropolymer binder oxidant;    a blowing agent effective to render the foamable igniter composition porous; and    a crosslinking agent effective to structurally stabilize the foamed igniter substance;    wherein, upon being heated to a predetermined temperature, the foamable igniter composition forms the foamed igniter substance.    
     
     
         2 . The foamable igniter composition of  claim 1 , wherein, upon being heated to a predetermined temperature, the foamable igniter composition forms a resilient foamed igniter substance.  
     
     
         3 . The foamable igniter composition of  claim 1 , wherein the fluoropolymer binder material oxidant additionally imparts adhesive properties to the foamable igniter material effective to adhere the foamed igniter substance to an associated surface.  
     
     
         4 . The foamable igniter composition of  claim 1 , wherein the fluoropolymer binder material oxidant comprises a fluoropolymer elastomer material.  
     
     
         5 . The foamable igniter composition of  claim 1 , wherein the fluoropolymer binder material oxidant is selected from the group consisting of dipolymers of vinylidene fluoride and hexafluoropropene, terpolymers of vinylidene fluoride, hexafluoropropene and tetrafluoroethene, and combinations thereof.  
     
     
         6 . The foamable igniter composition of  claim 1 , wherein the plasticizer comprises a fluorocarbon oil.  
     
     
         7 . The foamable igniter composition of  claim 1 , wherein the metal fuel is selected from the group consisting of aluminum, magnesium, alloys of aluminum and magnesium, and combinations thereof.  
     
     
         8 . The foamable igniter composition of  claim 1 , wherein, upon being heated to a predetermined temperature, the blowing agent at least partially thermally decomposes to render the foamable igniter composition porous.  
     
     
         9 . The foamable igniter composition of  claim 1 , wherein the blowing agent is selected from group consisting of aminoguanidine bicarbonate, ammonium oxalate, p-toluene sulfonyl semicarbazide, 4,4′ oxydibenzene hydrazide, acetone, ethyl acetate, butyl acetate, amyl acetate and combinations thereof.  
     
     
         10 . The foamable igniter composition of  claim 1 , wherein, upon being heated to a predetermined temperature, the crosslinking agent chemically reacts with the fluoropolymer binder oxidant to structurally stabilize the foamed igniter substance.  
     
     
         11 . The foamable igniter composition of  claim 1 , wherein the crosslinking agent comprises at least one bi-functional crosslinking agent and at least one peroxide crosslinking agent.  
     
     
         12 . A hybrid gas storage container for use in an automotive safety restraint system comprising: 
 the foamable igniter composition of  claim 1  applied to an inner surface of the hybrid gas storage container;    wherein, upon being heated to a predetermined temperature, the foamable igniter composition forms a foamed igniter substance that adheres to the inner surface of the hybrid gas storage container.    
     
     
         13 . A foamed igniter substance having a predetermined shape comprising: 
 the foamable igniter composition of  claim 1;     wherein the foamable igniter composition has a consistency effective to render the composition extrudable and, wherein, upon being heated to a predetermined temperature, the foamable igniter composition forms a foamed igniter substance having a predetermined shape.    
     
     
         14 . A damper pad cushion for use in an automotive airbag inflator comprising: 
 the foamable igniter composition of  claim 1;     wherein the foamable igniter composition, upon being heated to a predetermined temperature at a select pressure in a mold having a desired shape, forms a foamed damper pad cushion.    
     
     
         15 . An igniter stick for use in an automotive airbag inflator comprising: 
 the foamable igniter composition of  claim 1;     wherein the foamable igniter composition, upon being heated to a predetermined temperature, forms a foamed igniter stick.    
     
     
         16 . A method of making a foamed igniter substance, the method comprising: 
 heating the foamable igniter composition of  claim 1  to a temperature effective to at least partially decompose the blowing agent and foam the igniter composition; and    crosslinking the foamed igniter composition to form a foamed igniter substance.    
     
     
         17 . The method of  claim 16 , wherein during the heating the foamable igniter composition is heated to a temperature between about 160° and about 200° C.  
     
     
         18 . The method of  claim 16  further comprising applying the foamable igniter composition onto a surface to be coated by the foamed igniter substance prior to the heating.  
     
     
         19 . The method of  claim 16  further comprising extruding the foamable igniter composition into a predetermined shape prior to the heating.  
     
     
         20 . The method of  claim 16  further comprising loading the foamable igniter composition into a mold and applying pressure during the heating.  
     
     
         21 . A foamable igniter composition effective to form a foamed igniter substance, the foamable igniter composition comprising: 
 about 10 to about 60 composition weight percent of a fluoropolymer binder oxidant;    about 1 to about 40 composition weight percent of a plasticizer effective to render the fluoropolymer binder material oxidant flexible;    about 10 to about 50 composition weight percent of a metal fuel that is reactive with the fluoropolymer binder oxidant;    about 0.1 to about 30 composition weight percent of a blowing agent effective to render the foamable igniter composition porous; and    about 0.5 to about 5 composition weight percent of a crosslinking agent effective to structurally stabilize the foamed igniter substance;    wherein, upon being heated to a predetermined temperature, the foamable igniter composition forms the foamed igniter substance.    
     
     
         22 . The foamable igniter composition of  claim 21 , wherein the fluoropolymer binder oxidant is a dipolymer of vinylidene fluoride and hexafluoropropene.  
     
     
         23 . The foamable igniter composition of  claim 21 , wherein the plasticizer is polytrifluorochloroethylene.  
     
     
         24 . The foamable igniter composition of  claim 21 , wherein the metal fuel is magnesium metal.  
     
     
         25 . The foamable igniter composition of  claim 21 , wherein the blowing agent comprises p-toluene sulfonyl semicarbazide.  
     
     
         26 . The foamable igniter composition of  claim 21 , wherein the crosslinking agent comprises at least one bi-functional crosslinking agent and at least one peroxide crosslinking agent.  
     
     
         27 . The foamable igniter composition of  claim 26 , wherein the bi-functional crosslinking agent is trimethylolpropane trimethacrylate.  
     
     
         28 . The foamable igniter composition of  claim 26 , wherein the peroxide crosslinking agent is benzoyl peroxide.