PA/PU for airbag

Prototype side curtain airbag, partly inflated
 

After introduction of the driver airbag in the eighties, the growth of this safety product for the automotive has been tremendous.

After introduction of the driver airbag in the eighties, the growth of this safety product for the automotive has been tremendous. Besides, the development of variants for protection against rolling over, the so-called side curtains, and injury of legs and cervical has increased the need of fabric even more. Therefore a high-throughput technology like UD & Crossply production would be more than welcome. Rashly transforming the current production process of weaving a nylon fabric and subsequent silicone coating into a lamination route is no option. The thermoplastic properties of silicones are poor or completely absent and consequently an alternative matrix material is required. Polyurethanes, however, are a promising alternative because they combine thermoplasticity with high elasticity and good film-forming properties. The somewhat higher stiffness of such a polyamide/polyurethane crossply laminate is no objection for a side curtain airbag, because of their way of deployment: rolled up instead of folded. Besides, for this type the low permeability of crossply laminate is desirable in order to keep the bag inflated during the couple of seconds that a serious roll-over accident can last. Finally, especially the elaborate dimensions of a side-curtain airbag justify a production technology like UD & Crossply because of its high capacity. To demonstrate these benefits, Van Wees developed a prototype in which the seams were created by welding instead of stitching: another advantage of a crossply!