Pictures speak a thousand words

Welded airbag seam
 

Airbags are interesting products to be made, using the Crossply technique. The number of airbags in cars is expanding and applications in small trucks and other areas are being developed.

In the accompanying pictures of this item, you can see our latest developments in airbag Crossply technology. As you know, we make a Crossply laminate by means of at least two UniDirectional fiber layers. These UD layers are made with PA 66 yarns and the ones we used were not tangled or twisted. This has the large advantage that the fiber can be spread. Resulting in a large area covered by the fiber and thereby reinforcing the resin. The resin is thermoplastic and the spreading of the fiber limits the amount of resin to be applied to form a closed film.

But we have gone one step further. By alternating the fiber densities, in this case over a width of 40 millimetres, it is possible to make a very lightweight laminate. From the checkered appearance you may understand that there are areas with lower areal density and areas with higher aerial density. In fact, there are three different densities in this laminate. The weight of this Crossply laminate is 125 gram per square meter. It may not come as a surprise to you that it is very soft and pliable.

Another very interesting item is the possibility to weld the laminate. In the detail picture you can see that the weld is nearly crystal-clear. This means that the resin has been in its liquid stage and has fully impregnated the fibers. The result is a very strong bond between the two layers.

These pictures show a round airbag. You can imagine that it is also possible to make the airbag rectangular or square. And even more interesting, making a side curtain airbag with this technique. Side curtains differ from driver and passenger airbags in that they have to hold the air pressure inside the bags for several seconds. This requires a high level of seam strength and air tightness.

The present side curtain airbags are made by means of Jacquard weaving machines as a double fabric. This technique is very sophisticated but rather expensive. Due to the sizing of the yarns the bag has to be washed on large washing lines in order to be able to coat them for air tightness. Also the coating step is time consuming, relatively difficult and therefore expensive.

The Crossply technique is ones again able to combine several processes in far less steps as we have described above. We are testing these bags together with airbag manufacturers and the results are promising.

But let us make one thing clear, we hope you will never see a bag in operation in the car you are in.