Companies report value for medical device applications

PAWTUCKET, R.I.—Testing by a pair of suppliers to the medical device industry has "demonstrated a strong, chemical-resistant bond between thermoplastic elastomers (TPEs) and a clear copolyester substrate known for its toughness and chemical resistance," they said.

Eastman Chemical Co. and Teknor Apex Co. conducted the 90-degree peel testing that showed three Medalist brand medical grade TPEs from Teknor Apex provided bonds to four Eastman Chemical's Tritan brand copolymers.

"Specifically formulated to adhere to copolyester and other engineering thermoplastics, the Medalist compounds exhibited high levels of peel strength. The peel tests that showed high peel strengths with adhesive failures demonstrate excellent Tritan TPE over-molding performance. The combination of high peel strength and adhesive failure is considered desirable for over-molded applications," the companies said.

The bond strength between the two materials showed "very little loss even after soaking test samples for 48 hours in disinfecting chemicals," they said.

Medalist compounds tested included three grades: MD-34940, MD-34950, and MD-34959, with Shore A durometers of 42, 50, and 59, respectively. Tritan grades MX711, MX811, MXF321, and MXF421 were involved in the testing.

"By combining Medalist TPEs and Tritan copolyesters, manufacturers can improve the ergonomics, aesthetics, or functionality of medical devices," said Yubiao Liu, global medical technical platform lead, Eastman. "The combination of soft TPEs with rigid copolyester substrates can enhance grip, add texture or comfort, yield a tight seal, or provide damping characteristics."

Over-molding TPEs onto copolyester offers medical device designers both hard and soft characteristics. TPEs can be used for grips, gaskets, seals, and soft-touch elements on rigid medical components.