Development of impact modified engineering polyester resins for automotive applications

Polyethylene terephthalate (PET) has been successfully used as a fiber, packaging and film material for many years. PET compounds have also been used successfully for injection molding. The use of engineering thermoplastics in the automotive industry continues to expand. A current trend is to replace traditional body panel materials such as metal and SMC with engineering thermoplastics that can be injection molded. The use of the injection molding process to make body panels can save manufacturing time and reduce labor cost. The part made from engineering thermoplastics has to meet the same stringent requirements as traditional materials, including strength, toughness, dimensional stability, weather resistance, and chemical resistance. Recently, Ticona has worked with automotive companies to develop impact modified and reinforced engineering polyester resins to meet these requirements. An early developmental product, Impet (R) EKX-182, was successfully used in molding the structural body of Chrysler's Composite Concept Vehicle. This material has a good balance of strength and toughness, heat resistance, weatherability and cost effectiveness. Additional application opportunities led to the development of Impet (R) EKX-215 which has improved strength and toughness. Recently, we have developed a higher modulus, high impact strength material, Impet (R) EKX-221. In this presentation, we will review the development of these PET based engineering resins. Structure property relationships will also be discussed.