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The gel fraction and the curing rate of the silver mirror protective film according to the curing condition were investigated. Two-packaged polyurethane dry film made from acryl polyol and three different isocyanate curing agents (HDI-biuret, HDI-trimer and IPDI trimer) were built on the silver mirror layer in order to protect the layer. FTIR/ATR spectra showed the isocyanate content was clearly decreased and the gel fraction was increased as curing temperature and time were increased. The optimum curing condition of the silver mirror protective film was 80□ and 30 minutes. The dry film prepared with the optimum condition satisfied all tests in our materials specification for automotive interior parts. Moreover, the pencil hardness of the film containing dibutyltin dilaurate was stronger than the film without catalyst.

Physical properties of waterborne soft feel coatings for instrument panel were investigated. Soft feel coatings give warm and velvet touch for cold and hard plastic materials. A waterborne soft feel coating is composed of two parts. Part A contains polyester polyurethane dispersion (PE-PUD), OH-functional water dispersible polyurethane resin (PC-PUD) and OH-functional water dispersible alkyd resin (OH-PA). Part B contains hydrophilic hexamethylene diisocyanate trimer (HHDI). The soft feeling of a coated panel is related with the amounts of PC-PUD and OH-PA. The physical properties of coated panel are controlled by the NCO/OH ratio from Part A and Part B. The results from all reliability tests satisfied soft feeling, scratch, chemical resistance and fogging.