By Liz White UT staffLeverkusen, Germany-Electrical devices such as vacuum cleaners and dishwashers can now have the same noise and flame resistance that vehicle makers have been exploiting for years in car interiors, thanks to a new flame-retardant type of flexible moulded foam from Bayer MaterialScience AG. "Unlike conventional insulating mats, polyurethane moulded foams fill spaces exactly, even those with complex geometries. This enables them to absorb sound extremely effectively," said Alfred Schulz, a Bayer MaterialScience expert on the Bayfit foam. Formulation adjustment allows the foam to also stick to surrounding materials in appliances. Even at high vibrations, the foam will not slip, providing very good vibration absorption, Bayer's statement on the development explained. Using the new foam, designers can separate the housing and engine of an electrical device, from each other acoustically, Schulz said, in the BMS statement. In vehicles, as bulkhead cladding or under-carpet absorbers, these materials absorb solid- and air-borne noise, and will have a similar role in the household devices. For electrical devices, the flame retardance performance is "particularly demanding," Schulz adds. The new foam grades "conform to HF-1 or HBF (HBF is the highest possible classification) according to the strict US fire safety standard UL 94," he said. This test assesses behaviour of foam exposed to a naked flame for a minute and whether material dripping from the test piece due to heat ignites a layer of cotton wadding. Bayfit Tec's flame retardance comes from special polyols containing finely dispersed polyurea, where the particles have highly stable sedimentation and do not settle out. Design flexibility is also a benefit, says the German materials company, since the foam can be made in complex three-dimensional forms with sharp variations in thickness and long flow paths, and cables and other parts can be insert moulded to fix them in place. "
