Anaheim, Calif. — Elkem Silicones USA Corp. has been working on its new process for liquid silicone rubber for a few years, and now it's ready to show the industry.
The company officially launched LSR Select, a process focused on producing LSRs more efficiently by being able to manage cure speed. It also allows molders more options as Elkem's new process can blend durometers to an exact number. For instance, instead of scaling up by 10, the firm can precisely mix materials to create an exact Shore-A hardness.
Elkem demonstrated the process at the recent Medical Design & Manufacturing West show in Anaheim.
"This is really game-changing for the marketplace because there's a lot of two-component material that people would like to have overmolded to liquid silicone rubber," said Chris York, North American president for Elkem Silicones. "It's been impossible to do that in the past because the temperature would degrade the plastic. There are a lot of unique things material science people in the industry can start to think about doing to enhance the performance value of their parts with liquid silicone rubber."
Getting ratios to be exactly perfect to have full utilization of the silicone product is an ongoing issue with many molders, York said. A traditional LSR process takes two components and flows them through a pump into a static mixer.
What LSR Select does is switch when the catalyst and inhibitor are mixed. Instead of mixing a Part A and Part B together, the molder takes an LSR compound that contains the minimum amount of inhibitor in the base chemistry. That is then mixed in-line with whatever additional inhibitor is needed, followed by a platinum catalyst immediately before molding. The result is molders now have control of how much inhibitor and catalyst are injected in-line to optimize cure kinetics and efficiency.
Elkem developed the system and provided the chemistry, then partnered with Elmet to develop the machinery. LSR Select went operational at Elkem's York, S.C., facility in the summer of 2017.
"Now we want to get the touch and feel in with the industry," York said. "People that have been using liquid silicone rubber for the last 20-30 years are used to waking up in the morning, using a two-component material and producing parts. That has worked really well, but now we can actually change the game and enhance their productivity, improve their cost positions and put them in a position to now uniquely develop an end part that's different from others that they're competing with on the marketplace."
York said that those efficiency improvements vary depending on the part and the compound used. But in general, LSR Select provides a minimum of 25 percent productivity improvement in cure speed, which York said has been enhanced up to more than 50 percent on some occasions.
Elmet's technology also has allowed for LSR Select to let molders custom compound utilizing different streams, York said. The ability to zero in on a Shore-A hardness is also generating interest among its customer base.
"You can tweak any formulation, take a base and add any additive you want," Mehdi Abbadi, global business unit director for Elkem's eXtensio Elastomers, said. "In the LSR industry, you had one choice, A and B. You mix them, and you have one set of products. What we are giving with LSR Select is to give customers an option to go to custom compounding with LSRs."
With silicone capacity tightening globally, molders are looking for every opportunity to lower costs for their products without sacrificing margin. York said the firm also is seeing increased demand for low-temperature molding because now medical devices are being combined with drugs and electronics.
