Foam materials Such PE/PU composites can be used to produce large yet lightweight, rigid mouldings that are also pleasant to touch and have good sound-insulating properties. This combination of properties makes them particularly suitable for use in trucks, for example for the driver's cab trim. Focus - Sandwiches combining paper honeycomb, glass fibre mats and a polyurethane spray system are used in production-line vehicles, for parts such as trunk floors and sliding roof cassettes. - Thermoplastic-core sandwiches are less sensitive to humidity and moisture than their paper honeycombbased counterparts. - Sound-insulating composites with a soft-touch surface can be produced in a single processing step from polyurethane sandwiches and a polyethylene foam. Fig. 5: Acoustic measurements confirm the sound-insulating effect of composites based on the polyurethane spray system and foam. Innovative polyurethane roof module concept Bayer MaterialScience is also working on alternative roof module concepts, in which polyurethane sandwiches based on Baypreg® F play an important role. These modules should be 25% lighter than conventional sheet steel roof modules. The concept is based on the Multitec® polyurethane spray system that is sprayed into an open compression mould. This solid, non-reinforced topcoat determines the surface quality of the component. A light honeycomb core and two outer layers made of glass fibre mats are then combined to produce a semi-finished sandwich with an edge that has no core layer. The whole package is sprayed with the Baypreg® F two-component polyurethane system, and cut long glass fibres are additionally applied to the core-layer-free edge of the glass fibre mats. Finally, the sandwich composite system is compressed. The edge reinforced with glass fibre mats/long glass fibres gives the roof module high torsional stiffness. It also allows the integration of inserts so that add-on parts such as handles can be assembled more easily. The central honeycomb sandwich section saves weight and ensures high flexural strength. The IMC process could conceivably be integrated into the manufacturing process, thus allowing the production of components that have already been treated with a primer or base coat. More information: www.bayermaterialscience.com No45 November-December 2008 / jec composites magazinehttp://www.bayermaterialscience.com http://www.oxeon.se/