DETROIT – Build a better mousetrap and the world will beat a path to your door. Henkel Corp.’s brand new high-damping foam will not solve auto makers’ weight and fuel economy woes by itself, but it is one small step in the right direction.
The product is so new, officials at Henkel’s booth at the SAE World Congress here say they don’t even have literature on it. Nevertheless, they say word has gotten around, and is generating much interest among automotive engineers searching high and low for new ways to reduce vehicle mass.
Weighing in at a mere 1.3 oz. (38 gm) in a typical application as a roof-mounted sound damper, the foam (named HDF), is many times lighter than the usual solution for “boom” and other roof-related noise, vibration and harshness problems: a tarry swatch of material known as a bitumen pad (pronounced “bitchmen”).
A typical bitumen pad easily can weigh a comparably hefty 18 oz. (520 gm), and is attached to the vehicle roof before the headliner is installed.
HDF foam also can be used inside door panels to replace bitumen pads or gobs of adhesive that are plopped in key areas to damp vibration and prevent panel flexing known as “flutter.”
Ted Hayden, business development manager, parts and foams-Henkel Adhesive Technologies, says HDF starts out as a relatively small extruded hard part that is strategically placed on a roof panel or within a door prior to the vehicle going through the paint process.
Once the material is exposed to the high heat of the assembly plant paint-bake oven, it expands like bread dough into a soft closed-cell foam that swells to a predetermined volume 200% to 700% larger, becoming a gossamer pad or plug that tightly bonds to the metal surfaces it touches.
This provides big improvements in NVH, compared with the previous methods and at a fraction of the weight, Hayden says.