A High Speed Impact Study of Impact-Modified Polycarbonate Resins for Instrument Panel Applications

New car design features, warranty extensions and federal regulations require auto manufacturers to select tough, and long-lasting engineering thermoplastic resins for instrument panel (IP) applications. Two such IP materials, Makrolon T-7855 polycarboanate(an impact-modified resin) and Makrolon DP-1-1070 polycarbonate (an impact-modified high modulus resin) were studied by high-speed impact tests. The results show that both materials maintain high impact strength from 5 mph to 32 mph test speed, and from -30°C to 23°C in the most common part thickness of .100″ to .125″. After 12 weeks aging, both T-7855 and DP-1-1070 showed excellent retention of impact strength. A new approach to derive meaningful and consistent energy management numbers for glass reinforced impact-modified PC resins at low temperature is also presented.