MATERIALS | MEDICAL
Right: Hexpol TPE has
developed a range of Mediprene TPE compounds
a compound or there is the potential to change, this can reset the whole testing programme, cost thousands of dollars and force the project back by months, adds Huddleston. Future developments at United Soft Plastics for the medical market could involve plastics with chemical resistance to toluene, alcohol and
acetone, while also having 150℃ continuous heat resistance and be rapidly mouldable, adds Huddleston. “Current solutions are more than $10/ lb for raw materials and have long cycle times,” he says. “The plastics industry is still relatively young and the feedstock for TPE was only fully commercialised less than 30 years ago. Hopefully in 20 years, this problem will be solved and commercialised, and metal replace- ment by high-performance plastics can become the next big trend in our industry.” Hexpol TPE says the medical device supply chain has inevitably been greatly impacted in the past year as it has pivoted production to meet the demands that Covid-19 has brought. “In particular we have seen higher demands for translucent and transparent TPE materials for use in various kinds of face masks,” says Niklas Ottosson, Technical Manager – Medical. “Customers are looking for soft-touch materials with high levels of transpar- ency, that, where needed, can be sterilised with gamma, ethylene oxide and steam. Another area of high demand has been highly elastic TPE materials for the bands on face masks. These materials need to deliver on tensile and stress recovery perfor- mance.”
He says: “Covid-19 is a truly global event, with
requests coming from all over the world. We have also seen changes in timescales as projects are faster to commercialisation. From material recom- mendation and sampling, through to production and delivery, our medical team has been required
Below: USB socket protection on Osiris respiratory device from Air Liquide Medical Systems (ALMS). Developed in close collaboration with Kraiburg TPE, the articulated component is moulded by Nextis in Thermolast compound, which delivers a balance of durable mechanical properties and aesthetics, ease of injection moulding and reliable resistance against professional cleaners
to give fast response and support to meet the unprecedented demand. As we move into global vaccination pro-
grammes, we are waiting to see how this may affect demand patterns, possibly with efforts focused on drug delivery and syringe production.” Hexpol TPE’s latest developments for medical
applications include the Mediprene range of TPEs with grades for solvent bonding. The company says that it is common to join tubes with injection moulded components, such as connectors, by solvent bonding. Traditional TPS-based formula- tions do not bond well with solvent – cyanoacrylate glue with or without primer is an alternative to achieve high bond strength in these situations. However, Hexpol TPE has also developed a range of Mediprene TPE compounds that achieve high bond strength when applying solvents such as cyclohexanone. Mediprene solvent bondable TPEs for injection moulding are available in hardnesses from 60 Shore A to 45 Shore D and can be further expanded based on application requirements. The grades are transparent, and the tubing grades also offer good kink resistance properties. Kraiburg TPE and French medical components
specialist Nextis have developed an articulated cover designed to protect the USB port on respira- tory devices against dust and splash water entry. The part is moulded in Thermolast compound that delivers a balance of high mechanical properties and aesthetics, ease of injection moulding and reliable resistance against professional cleaners. As a system supplier of medical components and assemblies, Nextis is moulding several parts for an advanced respirator from Air Liquide Medical Systems, including a flexible protective cover for the device’s USP port. The cover is clipped to the device housing and has a hinged closure that ensures the sealing of the USB socket, when not in use, against the entry of dust particles, splash water and foreign objects.
The TPE compound selected for the IMAGE: ALMS 24 INJECTION WORLD | January/February 2021
www.injectionworld.com
IMAGE: HEXPOL
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