Henkel Technologies is collaborating with PSA Peugeot Citroen

A new closed cell polymer foam technology that promises significant reductions in structure-borne noise in automotive car bodies is at the late stage of development by car maker PSA Peugeot Citroen and plastics materials group Henkel Technologies.

The Dissipative Wave Barrier technology combines a polyamide structural liner with an expandable epoxy-based resin that is placed within body cavities during assembly. Subsequent exposure to the high temperature of the body E-coat painting process – up to 200°C – causes the epoxy resin to expand in-situ to form a high damping closed cell foam.

Speaking at EPN’s Plastics in Automotive Interiors conference in Prague last week, Henkel Technologies acoustic centre manager Jean-Luc Wojtowicki said the liner technology improved on existing solutions, which use separators to form closed chambers in the body cavities, by preventing the formation of standing waves.

Prototype systems have reduced sound levels at the driver’s ears by 2-3dB. This gain can be used by the car maker to further reduce cabin noise levels or to simplify manufacturing. “Our aim is to move parts from the trim shop to the body shop,” said Wojtowicki. He said the company can reliably form the closed cell foam in-situ. Work is now focused on further reducing the cost of the systems prior to commercialisation “in the near future”.