Materials: Copolyester Designed for Electronics Housings in Medical Devices

Eastman Chemical, Kingsport, Tenn., featured MXF221 copolyester at MD&M West 2018 in Anaheim, positioning the material as an alternative to polycarbonate blends in device housings—one that can better withstand the potent disinfectants increasingly deployed in hospital settings to combat the spread of resistant bacteria.

To help prove that heightened chemical resistance, and benchmark other materials, Eastman Chemical’s Yubiao Liu, applications development associate, developed a four-step 24-hour testing protocol and apparatus to evaluate the long-term resistance of plastics to various disinfectants.

According to the company, MXF221 retains more than 90 percent of its original impact strength after exposure to powerful disinfectants, reportedly besting polycarbonate blends it would compete against in an application like housings.

In addition to good impact strength and chemical resistance, Eastman reports that MXF221 is well suited for device housings due to its flame resistance—UL 94 V2 rating at thicknesses of 1.5 and 3.0 mm—and its colorability. Color matching is available eliminating the need for paint which often fairs even worse than base resins when exposed to aggressive disinfectants.

Initially Eastman developed MXF121, but created MXF221 and launched it in 2017, following a customer request for a fully compounded grade. In addition to color matching, at MD&M, Eastman displayed samples that had been laser marked.