Thermoplastic elastomers play a key role in wearables, one of the hottest markets today — but challenges remain in designing plastics that come into constant contact with your body and perform demanding functions, according to speakers at the Society of Plastics Engineers’ TPE TopCon 2016.

To fashion soft materials for wearables, the materials industry traditionally has pumped in additives to existing plastics, said Chris Schroder, DSM Engineering Plastics’ global business manager of Arnitel and Armite A materials.

But he said future devices in medical wearables will need things like integrating an antenna substrate into a flexible strap.

Better solutions

“If we want to grow in the market of wearables, we need to aim for better solutions in the medical area, and this is where there’s still a huge hurdle for the industry,” Schroder said.

But success in medical wearables could bring fast growth and development of new technologies, he said.

And even in other, more common devices like a smartwatch, there are issues of skin irritation of the strap that can cause rashes, and unpleasant smells, plus the need to add more measuring devices inside the product, Schroder said. “Skin compatibility needs to be rapidly improved,” he said.

TPE applications in wearables

TPE applications in wearables include head set cables, flexible connectors, grips and ultrathin keyboards, Schroder said.

Other challenges include customer demands for bio-based polymers in wearables.

“We really need a serious step and a serious attitude. You can’t solve this with mixing and blending. We really need new materials,” Schroder said.

Another speaker, Hossam Metwally, principal engineer at Ansys Inc., a consulting firm in Ann Arbor, Mich., said designing medical wearables like an insulin pump requires tubing that is flexible but cannot kink or twist. The pumps are typically the size of a cell phone, fitted with a display and buttons — making for a major engineering challenge, he said.

Metwally described how Ansys simulates the tubing extrusion, using reduced-order modelling to determine key parameters such as predicting the necessary die opening.

Steve Cranney, a development scientist at Kraiburg TPE, described his company’s work to develop a TPE for electronics and portable electronics devices. Kraiburg is still in the development stage, but the company has met all of its original targets for performance of the new material.

Cranney declined to talk about specific applications. “There’s some additional testing that we have going on right now,” he said.