DSM Launches The First Hydrolysis Resistant Arnite A Polyester For Dimension-Critical Auto Parts

As a result of continuous engine downsizing, particularly in the compact car segment, temperatures under the hood are going up, putting extra demands on plastics components used in this area. On top of this, identical electronic components are used in vehicles sold and used worldwide, which means they need to operate under a wide range of temperature and humidity conditions. Therefore, there is an increasing need for materials that retain key properties such as strength, stiffness and impact strength under demanding hot-humid conditions.

“Injection molded parts from conventional PET lose as much as half of their tensile strength after 1000 hours at 85°C and 85% relative humidity,”says Wouter Gabrielse, Automotive Segment Manager for DSM. “Parts made from DSM’s new hydrolysis resistant Arnite A PET keep around 90% of their initial strength under the same conditions. This was proven in simulated conditions in our laboratory. The performance we have achieved is quite spectacular.”

Arnite A-X07455 enables substitution of metals or higher cost engineering plastics such as polyphthalamides (PPA) and polyphenylene sulphide (PPS) in automotive parts that require high dimensional accuracy, good chemical resistance, and very good mechanical properties. It will enable car makers to save costs and improve fuel efficiency through light weighting.

This hydrolysis resistant Arnite A is being targeted at a variety of automotive under-the-hood applications, including throttle valve bodies, sensors, air control valve housings, electronic throttle control (ETC) and exhaust gas recirculation (EGR) covers, and ignition systems. The new product, apart from being highly hydrolysis resistant, also exhibits high stiffness, strength and dimensional stability. Arnite A-X07455, which contains 50% glass reinforcement, has a tensile stress at break of 200MPa, according to ISO 527.

“Arnite A has been proven to be the material of choice in automotive safety applications like brake booster valve bodies for many years” says Gabrielse. “With the new hydrolysis resistant grade we can enter into applications that are closer to the engine and which until now have never been achievable with PET.”