A panel of perforated thermoplastic material having sound and shock dampening characteristics comprised of a perforated honeycomb core and either whole or perforated facing sheets, thermal compression bonded to the core. The core can be faced on one side only, or on both sides to create a pad or panel...http://www.google.fr/patents/US5180619?utm_source=gb-gplus-shareBrevet US5180619 - Perforated honeycomb
