Development New Organic Composite Materials with Excellent Long-Term High-Temperature Durability and Reliability for Automotive Parts

In recent years, the emerging technology competitions in automotive industry are improving engine efficiency and electronizing for coping with stringent fuel-economy regulations. However, fuel-economy technologies such as engine down-sizing and numerous electronic parts entrust burden plastic materials acing as mainly electric insulation and housing to have to be higher performance, especially temperature endurance. Engineering plastics (EPs) have critical limitations in terms of degradation by heat. Heat-resisting additives in EP are generally used to be anti-degradation as activating non-radical decomposition of peroxide. However, it could not be effective way to impede the degradation in long term heat aging over 1,000 hours at high temperature above 180 °C. In this study, we suggested the new solution called ‘shield effect’ that is purposeful oxidation at the surface and local crystallization of EP to stop prevent penetrating oxygen to inside of that. Ethylene diamine tetra acetic acid (EDTA) and Citric acid (CA) are used as additives for surface oxidation. We added the EDTA and CA to Nylon co-polymer of PA6T/6I-PA66 and made test specimens. Surprisingly, physical properties maintained 5% under degradation rate at 250 °C, over 1,000 hours in contrast with Nylon added general additives. We confirmed surface oxidation and local crystallization of the Nylon by using Energy Dispersive X-ray Spectroscopy (EDX) and X-ray Diffraction Spectroscopy (XRD). Base on this result, we adopt the new materials to high temperature needed automotive parts in engine such as Battery Fuse Terminal (BFT) and Multi Fuse Terminal (MFT), in exhaust system such as Muffler.