At first, LSR Select, a base polymer material commercialized in 2018, was touted for saving production time by reducing cure times for liquid silicone rubber.
Oslo, Norway-based Elkem ASA, a global silicones materials supplier, said it optimized the cure kinetics of the LSR Select brand and improved cycle times by between 15 and 40 percent.
More recently, the material is proving to be a breakthrough by achieving low-temperature curing, according to J. Christopher York, president of Elkem Silicones USA Corp., a New Jersey-based division.
LSR Select can cure at 80° C compared with 160° C for traditional two-component LSR, York told Plastics News. This means LSR Select can be used in a wider range of applications without damaging temperature-sensitive components, such as plastics, electronics and batteries, in both the two-shot and overmolding processes.
"The thought of running at 80° C has been a wow factor because it's so unique to the marketplace," York said.
Founded in 1904, Elkem supplies silicon-based materials from quartz to specialty silicones to the health care, aerospace, automotive, construction and other markets. The company has 6,300 employees and nine manufacturing sites. Sales were $2.1 billion in 2019.
Earlier this year, Elkem put a spotlight on LSR Select's capabilities at the Medical Design & Manufacturing West trade show in Anaheim, Calif., calling it a next-generation LSR for formulation flexibility in addition to productivity and low-temperature cure.
The wider cure range opens doors to using silicone rubber in heat-sensitive applications, such as medical wearable devices, according to Elkem officials. They said LSR that cures at 160° C can't be used for products with electronics or overmolded with parts made of certain plastics such as polypropylene because it would melt.
"The whole idea of low-temperature cure is to allow overmolding on sensitive polymers and also electronic components," said Mehdi Abbadi, Elkem's global business unit director. "With this feature, LSR can be used in a completely different way targeting completely different applications. You no longer need mechanical tricks to bind together rigid plastics, such as PP and [polyethylene], with an elastomer like LSR. It saves time and expense to directly overmold these plastics."
LSR Select is a suitable material for wearable medical devices controlled with printed circuit boards that help patients manage their health by monitoring parameters, such as blood and glucose levels, added Julie Harber, Elkem's business development manager.
The advancement of wearable medical technology, which gathers data for patients to monitor for themselves or forward to their doctor, is growing along with demand from consumers to take control of their own health. The wearable medical device market was valued at $10.6 billion in 2019 and is growing at a compounded annual rate of 18.3 percent, according to the India-based market research firm P&S Intelligence. Market revenue is projected to reach $67.2 billion by 2030.
In addition to trials related to different substrates, LSR Select fared well when tested and compared to other LSRs used with sensitive electronics, Harber said.
"If you try to overmold a printed circuit board at 165° C, which we did prove out, it destroys the board. It's nonfunctioning," Harber said. "But in our trials, we were able to overmold that at 110° C, and it functions with the software program. We've proven that out in a couple trials, which is industry-changing."