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Physical properties of sprayed polyurethane skin for instrument panel were investigated. Optimized sprayed PU(polyurethane) composition for instrument panel was determined by reaction speed measurement, which were polyol of 6000 molecular weight and modified MDI (NCO=25%). For making sprayed PU skin, raw material was sprayed from 15 cm of distance, at 15 g/min of spraying rate, on 70°C of mold, with 75°C of raw material. Sprayed PU skin had lower density than PVC skin when investigating cross sections of skins using scanning electron microscope (SEM). But the reliability test results satisfied all the specification requirements like scratch, chemical resistance, contamination resistance and fogging. Tensile strength, hardness and elongation of sprayed PU skin were slightly changed during heat aging, but the changing rate was much smaller than those of PVC skin.

Since the environmental problems and new stricter regulations are forcing the industries to introduce more ecological materials for their products, biodegradable materials have attracted increasing attention. Among these materials, Polylactic acid (PLA) is remarkable for its modulus, strength, chemical resistance. However, PLA could not be used for automobile industries for its low heat resistance and impact strength. Therefore, in this study natural fiber was introduced as reinforcements in order to improve the properties of PLA. And for various experiments, Polypropylene (PP) was used as matrix resin instead of PLA. Especially for improving the properties of PLA composites, surface treatments, annealing, and adding rubber elements were performed. With surface treatments, we found that the mechanical properties of composite were improved. And with annealing treatment, we found the remarkable increase of heat resistance of PLA composite.