PARIS, Ky.—Not all of the world's coolest innovations happen in Silicon Valley.
Sometimes they happen in silicone recycling, smack dab in the middle of the Midwest.
With a 50,000-sq.-ft. brownfield project on 10 acres in the north-central portion of the state, Dow Chemical Co. and Paris, Ky.-based Circusil L.L.C. are pairing up to tackle this important issue as the world moves toward material circularity and a lower CO2 footprint.
"In the very near future, the circular economy will be on steroids," Eric Peeters, vice president for the Sustainability Performance Materials and Coatings segment for Dow, told Rubber News. "People are not going to continue to use things in a linear fashion.
"And Dow is doing a lot here. This is a fantastic fit with our corporate strategy as one of the leaders of the silicone industry."
The very essence of Peeters' role—to set and implement a holistic, cross-functional sustainability strategy, one that Dow can build around for growth—is evident in this pioneering project.
Dow expects the site to create between 35 and 40 jobs once it is operational, likely by the fourth quarter of 2024. Neither an investment at the site nor an annual capacity there (either input or output) was disclosed.
"This is a relatively short time-to-build. We will work quickly up to capacity, that's our plan," Peeters said.
He said the project already is scaled for commercial production. The initial waste input will be captive, coming from Dow's own silicone operations. Ultimately, "select," post-industrial customer waste will be part of the feedstock.
"Select, in this case, really refers to practicality—waste streams that we can access that are sufficiently large enough that also are not too far away," Peeters said.
That is on the waste side. On the output side, Dow does business with recycled silicone "where we can make an impact."
And geography plays a role here as well.
Dow has two silicone manufacturing locations in Carrollton and Elizabethtown, Ky., and its Mid-America warehouse also is in the Bluegrass State.
"It is critical to start thinking about silicone recycling ... and this is the first of its kind in North America," Peeters said. "This is something we really think will move the needle as far as waste capacity. Research and development is OK, but this puts something in place to start moving the needle as far as tonnage going through.
"This is a meaningful step for our industry."
While Dow will supply funding and the initial waste silicone rubber for the project, Circusil's groundbreaking technology provides the output, Peeters said.
The process enables the production of silicone fluids from silicone-based materials, "mitigating the detrimental environmental consequences of improper disposal, increased carbon footprint and reducing reliance on virgin materials," Circusil states on its website.
"By reintegrating silicone fluids into industrial applications, Circusil is working to ensure waste reduction and resource efficiency," the company said. "This vision embodies the very essence of circularity, where materials are continuously repurposed, echoing the harmony of nature's cycles."
Circusil's process conquers one of the major challenges in silicone recycling, which is cracking the cross-links developed in silicone rubber's unique curing phase.
Though much of the Circusil process is proprietary, essentially waste silicone rubber is cracked and purified, then reintegrated into industrial applications.
"They converge the silicone to be recycled into silicone that can go back to market, so it is a fully circular model," Peeters said. "They are the tech provider and the conversion party."
Dow then re-enters the supply stream picture.
"I think that is a part of our role as well, bringing recycled silicone back to market," Peeters said.
Most types of silicone rubber are eligible for the process, Peeters said, including LSRs, HCR (or gum silicone rubber) and room-temperature vulcanizates.
"(Circusil's) process actually breaks the cross-links and they make monomer again," Peeters said. "This gives you the freedom to make silicones of virgin quality once again.
"It's a really cool process."
The accessibility of silicone rubber—a tactile piece of material, in most cases—makes it easier to collect, and therefore to recycle.
Some silicone can't be captured, such as an anti-foaming agent in a detergent that goes into a municipal waste stream.
"But a part—an automobile part or perhaps a baby bottle nipple—those are tactile things that are easy to recycle," Peeters said. "Elastomers are the space we are focusing on.
"We don't have a lot of limitation either. There are some (recycled silicones) where we have to worry about application and specific functionalities—but the bulk of (silicone rubbers) can be treated at this plant."
While the chemistry hurdles were critical for Circusil, the biggest challenge to recycling silicone rubber may lie, ironically, in its versatility as an end product.
"I believe the real difficulty is in the dispersed use of silicone, as there are so many different applications," Peeters said. "The eco-collection system is really the most difficult challenge."
Still, Dow's partnership with Circusil marks a major step forward. And the Kentucky project may be just the beginning.
"The site is quite sizable already," Peeters said. "But we look at this as a first step toward something bigger.
"We want to move the industry forward ... this is our task, our burden. We are looking at circularity on a global scale, certainly, but we are starting in North America—this really reflects our ambition to lead silicone recycling at-scale.
"Hopefully, this is the start of a beautiful journey."
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