Low permeability airbag cushions having extremely low coating levels

Abstract

Coated inflatable fabrics, more particularly airbags to which very low add-on amounts of coating have been applied, are provided which exhibit extremely low air permeabilities. The inventive fabrics are primarily for use in automotive restraint cushions which require low permeability characteristics (such as side curtain airbags). Traditionally, heavy, and thus expensive, coatings of compounds such as neoprene, silicones and the like, have been utilized to provide such required low permeability. The inventive fabric utilizes an inexpensive, very thin coating to provide such necessary low permeability levels. Thus, the inventive coated airbag possesses a coating of at most 2.5 ounces per square yard, most preferably about 0.8 ounces per square yard, and exhibits a leak-down time (a measurement of the time required for the entire amount of gas introduced within the airbag at peak pressure during inflation to escape the airbag at 10 psi) of at least 7 seconds. All coatings, in particular elastomeric, non-silicon coatings, and coated airbags, meeting these criteria are intended to reside within the scope of this invention.

1 . An airbag cushion comprising a coated fabric, wherein the fabric is coated with an elastomeric composition in an amount of at most 2.5 ounces per square yard of the fabric, wherein the elastomeric composition comprises at least one elastomer possessing a tensile strength of at least 2,000 and an elongation of at least 180%, and wherein the airbag cushion exhibits a leak-down time after inflation of at least 5 seconds. 
   
   
       2 . The airbag cushion of  claim 1 , wherein the elastomeric composition comprises polyurethane. 
   
   
       3 . The airbag cushion of  claim 1 , wherein the coated fabric is woven from polyamide yarns. 
   
   
       4 . The airbag cushion of  claim 1 , wherein the coated fabric is woven from polyester yarns. 
   
   
       5 . The airbag cushion of  claim 1 , wherein the elastomeric composition is present in the form of a latex. 
   
   
       6 . The airbag cushion of  claim 1 , wherein the elastomeric composition is coated on the airbag fabric surface in an amount of at most 1.5 ounces per square yard. 
   
   
       7 . The airbag cushion of  claim 1 , wherein the elastomeric composition is coated on the airbag fabric surface in an amount of at most 1.2 ounces per square yard. 
   
   
       8 . The airbag cushion of  claim 1 , wherein the elastomeric composition is coated on the airbag fabric surface in an amount of at most 1.0 ounces per square yard. 
   
   
       9 . The airbag cushion of  claim 1 , wherein the elastomeric composition is coated on the airbag fabric surface in an amount of at most 0.8 ounces per square yard. 
   
   
       10 . An airbag cushion comprising a coated fabric, wherein the fabric is coated with an elastomeric composition, wherein the elastomeric composition comprises at least one elastomer possessing a tensile strength of at least 2,000 and an elongation of at least 180%, and wherein the airbag cushion exhibits a leak-down time after inflation of at least 5 seconds. 
   
   
       11 . The airbag cushion of  claim 10  wherein the elastomeric composition comprises polyurethane. 
   
   
       12 . The airbag cushion of  claim 10 , wherein the elastomeric composition is present in the form of a latex. 
   
   
       13 . The airbag cushion of  claim 10 , wherein the elastomeric composition is coated on the airbag fabric surface is a woven or a sewn cushion 
   
   
       14 . The airbag cushion of  claim 10 , wherein the elastomeric composition is coated on the airbag fabric surface in an amount of at most 2.0 ounces per square yard. 
   
   
       15 . The airbag cushion of  claim 10 , wherein the elastomeric composition is coated on the airbag fabric surface in an amount of at most 1.5 ounces per square yard. 
   
   
       16 . The airbag cushion of  claim 10 , wherein the elastomeric composition is coated on the airbag fabric surface in an amount of at most 1.2 ounces per square yard. 
   
   
       17 . The airbag cushion of  claim 10 , wherein the elastomeric composition is coated on the airbag fabric surface in an amount of at most 1.0 ounces per square yard. 
   
   
       18 . The airbag cushion of  claim 10 , wherein the elastomeric composition is coated on the airbag fabric surface in an amount of at most 0.8 ounces per square yard.