PAWTUCKET, R.I.—Teknor Apex Co. developed a new series of medical-grade thermoplastic elastomer compounds for overmolding applications to produce wearable devices.
The TPE compounds, which are sold under the brand name Medalist, offer strong adhesion to polycarbonate and PC alloys as well as "enhanced" resistance to chemicals, depending on the formulation, according to a company news release.
The Medalist line includes compounds in 50, 60 and 70 Shore A grades (MD-34900 series) for general medical overmolding applications and 75 Shore A (MD-36975 series), which was designed specifically to resist chemicals encountered by wearable devices, such as those found in lotions and disinfectants.
Teknor Apex recommends Medalist compounds for wearable devices where TPEs can contribute comfort; soft-touch or cosmetic grips for handheld devices, instruments and medical device housings, and seals and gaskets.
"Medalist TPEs are excellent alternatives to liquid silicones used in overmolding because they do not require the use of a primer, have a shorter cycle time (avoiding the lengthy curing process), and can be processed on conventional injection molding equipment," Ross van Royen, senior market manager for Teknor Apex, said in the release.
The Teknor Apex staff worked with Covestro L.L.C. experts to test the compounds by overmolding them onto various medical grades of Covestro brand PC (Makrolon) and PC alloys (Bayblend and Makroblend), using both insert and multi-shot molding. The joint project involved tests to evaluate processability in addition to adhesion and chemical.
Peel strength data showed the Medalist compounds exhibit excellent adhesion to Covestro's engineering thermoplastics, the release said.
The two companies will present a co-authored white paper with details of the experiments and product performance at MD&M West in Anaheim, Calif., from Feb. 9-11. Teknor Apex will exhibit at Booth 2121and Covestro will be at Booth 2221.
The new compounds for the medical device industry are an outgrowth of work to develop overmolding TPE formulations for consumer products, according to van Royen.
"We've made substantial investments in adhesion-modified technologies for TPEs, increasing our understanding of adhesion, developing more cost-effective formulations, and improving the bonding capabilities of these products in complex part designs," he said.
The Medalist series compounds are made with FDA-listed food-grade ingredients and are ISO 10993-5 compliant for biocompatibility. The compounds are produced at multiple Teknor Apex facilities for supply security.
Founded in 1924, Teknor Apex operates 13 manufacturing plants in the U.S., Belgium, Germany, China, and Singapore.
2019 was a significant expansion year for the company and 2020 will be similar, President Suresh Swaminathan told Plastics News in November. Between the plants in Germany and Singapore, the firm will increase its TPE compounding capacity by 15 percent.
"With these strategic initiatives, we will become one of the few compounders globally who will have local capabilities to provide TPEs and TPVs (thermoplastic vulcanizates) in the three major world regions," he said.
In addition to TPEs, Teknor Apex produces flexible and rigid vinyl, nylons, color masterbatches, specialty chemicals and hoses.