Low permeability airbag cushionshaving film coatings of extremely low thickness

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 permeability. The inventive inflatable fabrics are primarily for use in automotive restraint cushions that 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 necessarily low permeability levels. Thus, the inventive coated inflatable airbag comprises a film laminated on at least a portion of the target fabric surface wherein the film possesses a tensile strength of at least 2,000 and an elongation at break of at least 180%. The film provides a low permeability airbag cushion exhibiting a leak-down time of at least 5 seconds as well as a very low packing volume (for more efficient use of storage space within a vehicle) for the target side curtain airbag.

Description

[0001] This application is a continuation-in-part of co-pending application Ser. No. 09 / 557,643, filed on Apr. 25, 2000, which is a continuation-in-part of co-pending application Ser. No. 09 / 501,467, filed on Feb. 9, 2000, which is a continuation-in-part of Ser. No. 09 / 350,620, filed on Jul. 7, 1999, which is a continuation-in-part of Ser. No. 09 / 335,257, filed on Jun. 17, 1999; this application is also a continuation-in-part of co-pending application Ser. No. 09 / 406,264, filed on Sep. 24, 1999. These parent applications are herein entirely incorporated by reference.[0002] This invention relates generally to coated inflatable fabrics and more particularly concerns airbag cushions to which very low add-on amounts of coating have been applied and which exhibit extremely low air permeability. The inventive inflatable fabrics are primarily for use in automotive restraint cushions that require low permeability characteristics (such as side curtain airbags). Traditionally, heavy, and thus...

AI Technical Summary

Benefits of technology

[0010] In light of the background above, it can be readily seen that there exists a need for a low permeability, side curtain airbag that utilizes lower, and thus less expensive, amounts of coating, and therefore exhibits a substantially reduced packing volume over the standard low permeability type side curtain airbags. Such a coated low permeability airbag must provide a necessarily high leak-down time upon inflation and after long-term storage. Such a novel airbag and a novel coating formulation provides marked improvements over the more expensive, much higher add-on airbag coatings (and resultant airbag articles) utilized in the past.

[0011] It is therefore an object of this invention to provide a coated airbag, wherein the coating is present in a very low add-on weight, possessing extremely high leak-down time characteristics after inflation and thus complementary low permeability characteristics. Another object of the invention is to provide an inexpensive side curtain airbag cushion. A further object of this invention is to provide an highly effective airbag coating formulation which may be applied in very low add-on amounts to obtain extremely low permeability airbag structures after inflation. An additional object of this invention is to provide an airbag coating formulation which not only provides beneficial and long-term low permeability, but also exhibits excellent long-term storage stability (through heat aging and humidity aging testing). Yet another object of the invention is to provide a low permeability side curtain airbag possessing a very low rolled packing volume and non-blocking characteristics for effective long-term storage within the roofline of an automobile.

Problems solved by technology

Such a coated low permeability airbag must provide a necessarily high leak-down time upon inflation and after long-term storage.

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