Polyurethane Foam as an Integral “Core” Component of Automotive Headliner

Automotive headliner technology today consists of designing and manufacturing complex sandwich constructions with decorative, structural, acoustical, and energy-absorbing functions. The use of polyurethane semi-flexible foam as a core material for headliner construction has witnessed a substantial global increase. Further sophistication of headliner construction imposes additional demands requiring high performance semi-rigid foam. This paper discusses the desirable properties to be achieved, material characteristics, and processing issues. An ideal headliner foam should combine high stiffness and rigidity, low density, specific and uniform airflow, acoustical properties, dimensional stability over the wide range of temperatures, and thermoformability. Design of headliner semi-flexible (semi-rigid) polyurethane foam requires more innovative approaches than those used for conventional foams. Introducing foam into headliners puts additional constraints on the foam, due to the variety of composite constructions and methods of headliner manufacturing. Optimal foam characteristics for headliner fabrication cannot always be easily defined a priori. Results derived from customary test methods and additional testing, in particular—thermoanalytical techniques such as DMA—can be used for foam characterization and headliner processing optimization. Future demands for headliner foam that can be foreseen are a lower weight with increased stiffness, recyclability, energy management, shorter processing cycle, and reduced overall cost.