| abstract |
A multilayer foam composite element whose total thickness d comprises at least three layers composed of an open-cell foam, where at least one of the internal layers has recesses and the two outermost layers have no recesses, whereinn i) the volume of the recesses in the internal layer having recesses is from 20 to 70% by volume, and ii) the thickness of the layer having recesses is from 20 to 80% of the total thickness |