Striving for circularity: 4 ways the rubber industry is advancing sustainability

It's one thing for an industry to say it's going to be more sustainable. It's another to take actionable steps toward a set goal.

Bill Niaura, Bridgestone Americas Inc.'s director of sustainable materials and circular economy, voiced a similar sentiment at this year's Clemson University Tire Industry Conference.

"We must radically rethink what we use to make tires," he said. During his talk, "Radically Re-Thinking Our Raw Materials Supply Chain," he said the only truly renewable resource in use in the industry is hevea natural rubber.

But this is changing.

Associations and companies alike are marking milestone achievements and backing initiatives like bio-based feedstocks, recovered carbon black and increasing markets for recycling end-of-life tires.

Across the industry, key players have stepped up their commitments to achieve net-zero carbon emissions by 2050, and this year, the industry has made some major strides toward this goal while developing a more circular economy along the value chain.

Companies around the world are searching for bio-based alternatives to petrochemical-derived products, and this year industry suppliers have come forward with a wide range of breakthroughs.

In early 2022, Synthos took a step forward in its long-term plan to shift away from coal.

The firm, alongside Lummus Technology and its Green Circle business, said that its bio-butadiene technology was ready for implementation and committed to building a bio-butadiene factory in Oswiecim, Poland, which will produce 40,000 metric tons per year.

"We will be able to produce synthetic rubber using butadiene that is not generated by fossil feedstock," Matteo Marchisio, director of tire materials and the synthetic rubber business unit for Synthos, had told Rubber News in the fall. "It will be 100-percent based on ethanol."

Over the summer, German distributor Biesterfeld A.G. began marketing a new filler product made from oyster shells, its bio-based CaCO3 filler Oysterlean.

Sascha Hennig, managing director of Biesterfeld Performance Rubber, claimed the product can replace carbon black in rubber products by up to 50 percent, offering an 80- to 90-percent lower carbon footprint.

In July, Italian tire maker Pirelli & C. S.p.A. began testing lignin as an alternative to carbon black, with plans to roll out a passenger tire with the wood-derived material.

Using lignin—a byproduct of the pulping process in the paper industry—in the rubber mixing process helped enhance the mechanical strength of the rubber, according to Pirelli, which referenced its use in bicycle tires.

Evonik Industries A.G. entered a partnership with Austria's Poerner Group and Thailand's Phichit Bio Power Co. for the commercial supply of sustainable Ultrasil-branded silica, derived from rice husk ash.

Evonik said in September that this partnership will use Poerner's process to generate sodium silicate from RHA using biomass energy, which will enable Evonik to deliver a carbon footprint reduction of up to 30 percent compared to its standard silica.

Sumitomo Rubber Industries Ltd., in October, announced a breakthrough in synthesizing biopolymers through a selective polymerization process using modified tomatoes.

The Japanese group discovered that using the modified tomato enzymes as a polymerization catalyst made it possible to select polymer initial monomers "at will," which would allow scientists to incorporate monomers that are more conducive to improving tire performance.

The new biopolymers, the company said, can help accelerate the development of what it described as "the ultimate fuel-efficient tires."

That same month, Birla Carbon and its Brazil-based partner GranBio Technologies were awarded $730,000 in grants to advance industrial scale factory and on-road trials of their nanocellulose dispersion composite rubber masterbatch.

The product is a bio-based rubber additive that, according to Birla, will improve rolling resistance and vehicle fuel economy.

And in what the two firms called a groundbreaking partnership, LanzaTech NZ Inc. and Sumitomo Riko Co. Ltd. teamed up in the fall to produce isoprene.

Sumitomo will provide rubber, resin and urethane waste, and LanzaTech will supply the technology to convert the waste into isoprene.

"This exciting partnership with Sumitomo represents an opportunity to make a significant positive impact on the production of rubber," said Jennifer Holmgren, CEO of LanzaTech, noting the global isoprene market is projected to be worth about $4 billion by 2025.

"We need new sustainable pathways for the production of rubber to avoid any impact on land and biodiversity," she said.

Manufacturers aren't just thinking about what sustainable materials go into their products, they also are considering how their products can be reintroduced into the value chain at the end of their lives.

Waste tire pyrolysis company Pyrum Innovations A.G. has been scaling up its recycling capabilities with a handful of partnerships.

In June, the firm partnered with Siemens A.G., to promote, optimize and scale its pyrolysis plants' technology and economy using Siemen's digitalization and automation portfolio.

This agreement came after Pyrum's March partnership with Continental, through which the tire maker's waste tire disposal subsidiary supplies ELT to Pyrum for recycling. By May 24 Pyrum had delivered 60,000 liters of "optimized pyrolysis oil" to Spanish partner Sisener Ingenieros S.L., marking a milestone achievement in the BlackCycle project for successfully optimizing waste tire pyrolysis.

In July, Pyrum began leading a joint venture, Revalit GmbH, to establish a pyrolysis facility with the capacity of 20,000 metric tons per year. The JV, comprised of several partners, is to be located in the port of Straubing, Germany, in lower Bavaria.

In September, Pyrum signed a memorandum of understanding with Unitank, a German tank terminals operator, to scale up its tire recycling technology.

The two companies plan to build up to 10 ELT pyrolysis facilities by 2030 across the European Union region, and each unit is to be equipped with at least three pyrolysis reactors with a recycling capacity of about 20,000 metric tons per year.

And in October, Pyrum received all official state approval needed to commission two additional recycling lines at its flagship processing plant in Dillingen, Germany, that will assist with this scale-up in tire recycling.

At the Smithers Recovered Carbon Black Conference in November, Michelin and Bridgestone presented their findings after a year-long investigation in recovered carbon black (rCB).

The two tire makers revealed that demand for rCB could reach 1 million metric tons by 2030—so long as recycling technologies continue to develop over the coming years. The companies now are aiming to establish an initial proposal for a grades definition and associated specifications for rCB, as well as coordinate with regulatory bodies to harmonize standards and help the global recycling "ecosystem" better understand the needs of the rubber industry.

"We strongly believe that proposing a global recovered carbon black standard, which was established with various stakeholders across the tire and rubber value chain, will allow us to transform tires at end-of-life into very high-quality raw materials that can be incorporated in new tires, which is essential in the industry's journey toward material circularity," said Sander Vermeulen, vice president of the End-of-Life Rubber Products Recycling Business at Michelin.

Orion Engineered Carbons took a step forward on its path to sustainability with the development of its second carbon black made from 100-percent renewable feedstock, Ecorax Nature 200.

The new carbon black, made from tire pyrolysis oil extracted from end-of-life tires, follows last year's launch of Ecorax Nature 100.

Celso Magri, director of global marketing and sustainability for rubber at Orion, told Rubber News that both carbon blacks provide a sustainable solution to the tire and rubber industry while matching the same performance properties as their virgin counterpart.

Pyrum Innovations in December also began supplying rCB for Schwalbe bicycle tires, closing the loop for the Ralf Bohle GmbH brand, which collects used tires through its own recycling system and supplies them to Pyrum for further processing.

In early December, the U.S. Tire Manufacturers Association revealed that the rate of growth for scrap tire generation is outpacing the rate of growth for ELT recycling.

Scrap tire generation increased by nearly 13 percent, according to the association's "2021 Scrap Tire Management Report," whereas markets that consume them only increased by 6 percent.

Throughout the year, USTMA has taken the lead on top priorities in the tire industry, including encouraging scrap tire market expansion during the June 14-16 congressional virtual fly-in; backing a retreading bill, H.B. 8165, that same month; and urging scrap tire use in infrastructure projects alongside the Tire Industry Association through a joint letter to President Biden, among other initiatives.

"We see scrap-tire recycling as a key part of our role in supporting a sustainable circular economy, and we have been steadfast in our efforts to promote market expansion," said Anne Forristall Luke, USTMA president and CEO. She added that the association will continue its commitment to expand opportunities for scrap tire management.

And the association is not alone in emphasizing the importance of ELT recycling, as companies throughout the tire industry have invested in and rolled out their own initiatives toward the cause.

In February, Bridgestone Corp. launched a joint research and development program to advance chemical recycling of waste tires.

The Japanese tire maker partnered with the National Institute of Advanced Industrial Science and Technology, Tohoku University, energy group Eneos Corp. and JGC Holdings Corp. to develop chemical recycling technologies to achieve "high-yield production of isoprene."

And in the spring, Bridgestone Americas Inc. entered a partnership with LanzaTech to pursue ELT recycling technologies—the company's first step toward a circular economy.

As part of the partnership, the two companies will co-develop an ELT recycling process with LanzaTech's proprietary CCT technology. The two companies said they will work to convert scrap tires into new materials and explore processes to create sustainable synthetic rubber that does not rely on petrochemicals.

Apollo Tyres Ltd. and Continental both have entered partnerships with waste tire recycler Tyromer Inc., bringing recycled rubber and ELT back into their tire production.

And on Aug. 2, the partnership between Bolder Industries Inc. and Liberty Tire Recycling L.L.C. came to fruition, wherein Liberty will supply scrap tires for Bolder's patented fossil fuel and steel mining processes.

Beginning in 2023, Bolder will process about 3 million scrap tires per year at its western Indiana location from Liberty's feedstock, and that number could increase to 6 million per year with further expansion in Terre Haute, Ind.

These companies, along with countless others this year, all have driven home the importance of circularity when it comes to working toward a sustainable future.

Because at the end of the day, if a product with sustainable materials ultimately ends up in a landfill, is it truly sustainable?

"Half of the path is sustainability, but there is the other half of the path, which is circularity," said Jason Stravinski, CEO of Michelin-owned Lehigh Technologies, during the Smithers Traction Summit in July.

"So as we start to judge things that are sustainable, I ask the question: Is it circular?"