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The long-and-winding road toward more circular tires

The industry is pushing for more ‘sustainable’ materials and pushing collection efforts, but recycled rubber is still more likely to find a home outside of new tires.

Waste tires

Waste tires ready for processing. Photo courtesy of Ecore

Ventures focused on circular economy advances haven’t historically represented a sexy funding category, but December and early January brought the closing of two high-profile investment infusions: $55 million for AMP Robotics, which is using artificial intelligence to reinvent recycling infrastructure, and $25 million for TerraCycle’s Loop venture, which combines e-commerce with reusable containers.

Indeed, if you poke deeper into developments during the long and winding road that was 2020, it appears more investors are becoming willing to kick the tires (so to speak) when it comes to companies focused on turning someone else’s waste into a saleable product that keeps said waste from winding up in a landfill. 

And one category that has received renewed attention in the past three months: Companies that turn tires no longer road-ready into materials that can be reused in everything from flooring to modified asphalt to artificial turf and even brand-new tires. While it’s still technically difficult to reclaim tires and put that material back into rotation in the same form as the original because of performance and safety considerations, plenty of companies are innovating to upcycle old tires into other materials — and a well-established ecosystem of recycling partners from which they can buy.

One of the great attributes of rubber is that it can be repeatedly upcycled.

Consider Ecore, which turns recovered tires into commercial flooring — something it’s been doing for years but is getting ready to scale more seriously. In December, it struck a deal with CommonWealth Equity Partners, a firm formed by Ecore CEO Art Dodge along with Robert Bernard, former chief environmental strategist for Microsoft, and Michael Derosa, former general partner with Element Partners. 

While Ecore has been around for several decades — in 2019, it diverted more than 112 million pounds of truck tires from landfills or incineration into its products — its new relationship with Commonwealth is meant to help Ecore scale its closed-loop manufacturing process and to invest in systems that will augment its ability to upcycle its own products, used by more than 10,000 customers.

"One of the great attributes of rubber is that it can be repeatedly upcycled," Dodge observed. "Although only a few customers take advantage of the ability to upcycle end-of-life flooring, Ecore is working on revising its takeback program to incentivize customers to upcycle their existing floor. Our plan is to take back Ecore products and upcycle them into future floor products for our customers."

Ecore sources its tires — primarily those from commercial trucks because they yield more rubber — from within Pennsylvania and the East Coast. Imported tires, Dodge says, are more likely to contain contaminants. The company’s flooring contains up to 95 percent post-consumer recycled content, according to its marketing materials. 

Ecore production

Material being processed in the Ecore production facility. Photo courtesy of Ecore

Let’s review the track record

When it comes to collection and reuse systems, plastics producers probably could learn a thing or two from the ecosystem created and nurtured by tire manufacturers to reclaim tires that are no longer roadworthy. In the United States, state regulations guide what happens to tires when they come off the axel. In Europe, it generally happens at the country-level, inspired by guidelines set by the European Union more than a decade ago. Figures quoted by Ecore estimate the total amount of tires discarded annually in the U.S. alone at more than 6 billion pounds. 

According to data from the U.S. Tire Manufacturers Association (USTMA), about 81 percent of "scrap tires" found a beneficial end use as of 2017 — although the biggest end use for almost half of what was collected was "tire-derived fuel," which includes incineration. Historical figures from the U.S. Environmental Protection Agency support that overall collection percentage, although the agency hasn’t been keeping that information up to date. The two other big applications are ground rubber (used in new rubber products, landscaping mulch, rubber mats and rubber-modified asphalt) and tire shreds for road and landfill construction, septic systems and leach fields.

"There is a lot of effort being put in by a lot of companies, a lot of smart people," said Paul Crehan, chief executive of Lehigh Technologies, a division of Michelin that specializes in turning recycled tires into micronized rubber powder, a substance used in everything from coatings to asphalt and, to a lesser extent, new tires.

We believe that an end-of-life tire has a lot of value. The main objective is to try to promote new and better applications to use the materials that we think have a lot of value.

What are the possibilities? A young startup called Pretred, for example, is working on ways to use reclaimed tires for road barriers. (It uses about 60,000 tires and 60,000 pounds of plastic for every 1,000 barriers.) Dutch company Black Bear is creating carbon black (the substance used to color inks and computer keyboard buttons) from upcycled tires. Norwegian tire recycling organization Wastefront is adapting its facilities to offer a more advanced method of pyrolysis, producing liquid hydrocarbons. 

And in Europe, two established companies in the ecosystem — Portuguese tire management company Valorpneu and multinational tire recycler Genan — have teamed up on an initiative called NextLap to explore the "zillion" potential applications for reclaimed tire rubber and other materials. Its partners in the R&D effort, managed by the innovation consultants Beta-i,  include an apparel maker, a sporting goods manufacturer, a shoe company, a couple of construction firms and an automotive parts supplier.

"We could help link these innovators to other organizations; we are not making innovations for the heck of it. We are trying to match our ideas with market ideas," said José Carvalho, director of business innovation for Genan.

"We believe that an end-of-life tire has a lot of value. The main objective is to try to promote new and better applications to use the materials that we think have a lot of value," added Paulo Silva, operations and logistics manager at Valorpneu.

What goes around comes around

While most people equate tires with rubber, that’s just one component of what cushions vehicles during their on-road and off-road journeys. Most are a composite of natural rubber (sourced from plants), petroleum (yes, there are plastics in tires), steel, nylon, polyester and silica.

Tires include different percentages of rubber depending on their intended use — a race car, for example, might use more to remain "sticky" on the track surface when accelerating through curves. For that reason, Lehigh’s Crehan said his company’s customers use a relatively minor percentage of micronized rubber in their designs — maybe 5 percent to 10 percent — although that can add up on a large production run. 

"There is a reason why each material is in there at the ratio that it is, and when you put an end-of-life micronized material back into a tire, it doesn’t provide the same chemical reactions," he said.

Andrew Thompson, global director for sustainability, strategy and integration with Bridgestone, also said reincorporating end-of-life tires back into the production system remains complex, because tire performance is closely associated with things such as fuel efficiency. Shifting the recipe will affect other factors. "Making a tire is like baking a cake. That has been a big challenge in terms of the closed loop approach," Thompson said. 

Ecore flooring at a Planet Fitness facility

Ecore flooring at a Planet Fitness facility. Photo courtesy of Ecore

Where the rubber meets the road 

Encouraging tire recycling and reuse is just one piece of the overall sustainable agenda for Bridgestone and other major tire manufacturers including Pirelli and Michelin. Bridgestone’s 2050 vision is to use "100 percent sustainable materials," said the company’s chief sustainability officer, TJ Higgins.  

That will see it focus on expanding its renewable sources for natural rubber, advancing circular economy practices — it includes micronized rubber powder in high-performance and agricultural tires, as well as pre-cured tread for retreads — and shifting to natural rubber substitutes such as guayule, a desert plant used as an emergency source back in World War II. "It depends on our ability to extract and purify, process and produce," Higgins said.

Michelin is also steering toward a 2050 vision of 100 percent sustainable materials. In June 2019, it unveiled the prototype of "airless" tires made of composite materials that could be on the road by 2024. Among the design elements the company is prioritizing include how to make tires lighter (which means less materials) and how to extend their useful life. It, too, is experimenting with new biosourced materials, including dandelions, Crehan said.

As an industry, we would like to live in a world where end-of-life tires would be something people would be willing to pay for.

Goodyear is also testing a variety of concepts, including a hybrid called Oxygene, 3D-printed using rubber powder from recycled tires and living moss growing in the sidewalls. The technology is also intended to be regenerative, with electricity generated by the tire’s rotation harvested and used to power onboard sensors.

Maureen Kline, vice president of public affairs and sustainability for high-performance tire maker Pirelli, said her company’s circular economy strategy is centered on modifying design and collaborating with other stakeholders to help create demand for specific applications, such as rubber modified asphalt. For example, the USTMA in December announced a partnership with nonprofit The Ray centered on studying the impact in using ground tire as part of the mix — probing questions such as how adding this material effects wear as well as the potential environmental implications. 

The goal is to encourage more use of this material for this application, helping create a market that is more profitable than alternatives such as tire-derived fuel.

"As an industry, we would like to live in a world where end-of-life tires would be something people would be willing to pay for," Kline said.

This story was updated on Jan. 26 .

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