Abstract
New and upcoming federal standards for occupant safety in automobiles and trucks have increased the need for impact energy management in automotive interiors. The National Highway Traffic Safety Administration (NHTSA) regulations continue to promote improvements in the areas of head, knee, and side impact.
Materials being used or considered for managing occupant safety have included steel, glass-reinforced polypropylene, ABS, polycarbonate, and expanded bead foam such as polypropylene or SMA. As requirements increase and applications become more sophisticated, the benefits of polyurethane technology have made PU the top candidate for many of these applications. Increasingly, polyurethane foams are used because of their energy-absorbing properties over a wide temperature range, moldability, design flexibility, and low weight. Recent studies have focused on rigid crushable polyurethane foam, primarily for the knee impact application. However, polyurethanes can provide a broad range of foam types that offer energy management potential for a wide spectrum of design intents.
ICI Polyurethanes has developed a portfolio of new energy management (EM) polyurethane foam systems which are CFC-free, water-blown, and low density. These products range from rigid to semi-rigid to viscoelastic foams. Each type of foam offers unique properties for various automotive interior applications. Rigid foams absorb energy primarily through a non-recoverable, physical crushing of the foam cells. On the other hand, semi-rigid and viscoelastic foams provide a viscous dissipation of energy with a slow shape recovery. This paper describes the development, static/dynamic impact properties, and processing of these new polyurethane EM foams.
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