Tailoring the Performance of Molded Flexible Polyurethane Foams for Car Seats

Abstract

The automobile seat is a major element of contact between the occupant, the vehicle and ultimately the road surface. Flexible polyurethane foams are the material of choice for this application, not only because of the economies offered by large scale operations, but also because the cushioning characteristics of the foam/seat assembly can be adjusted. Commercially useful foams can be made from a variety of polyurethane molding chemistries. Recent advances in polyol and copolymer polyol technology, together with multiple isocyanate choices and even new foam manufacturing technologies, present the foam producers, seat assemblers and seat designers with a myriad of options. The automotive original equipment manufacturers (OEM's) worldwide are looking for optimization of the balance between foam weight and foam specifications, with more emphasis than ever on comfort and durability. This goes with specific requirements for the various foam pads, i.e., front cushion, rear cushion, front back-rest and rear back-rest. This paper presents new data showing how the choice of molding chemistry impacts not only foam processing and physical properties, but also the comfort and durability that can be expected from the final seat assembly. Results from recent studies carried out by The Dow Chemical Company on a global basis and concentrating on static and dynamic fatigue, resiliency, vibration damping characteristics and humid aging, are presented in an effort to provide foam producers and users worldwide with up-to-date information useful in helping them to meet their present and future performance targets.