July/August 2019
By Katie Pyzyk
New markets for scrap tire rubber may be more challenging to find than those for other commodities, but processors and manufacturers are creating unique niches while breaking into areas where virgin materials previously dominated.
Identifying new end markets for recycled tire rubber has taken on heightened importance in light of recent trends. According to the U.S. Tire Manufacturers Association (Washington, D.C.), the proportion of scrap tires that found their way to beneficial end-use markets has declined from a peak of 95.9% in 2013 to 81.4% in 2017, while scrap tire generation continues to increase. To that need for new markets, add the public’s growing interest in sustainability, and conditions are ripe for manufacturers to find new ways to incorporate recycled content into their products. Tire recyclers have a role to play in innovation as well. “As an industry, we tend to think too much about scrap and not enough about what we’re going to do with it. We’re too focused on what it is instead of what it can be,” says Bo Barber, vice president of sales and marketing at Ecore International (Lancaster, Pa.).
When tire processors and consumers are innovating, they can be very tight-lipped about it. Those who pioneer new uses for scrap tire rubber may hesitate to share the details for fear that other, larger companies will horn in on the business. Thus, “it’s hard to get real data to understand exactly what’s happening” in the scrap tire sector, says Terry Gray, president of TAG Resource Recovery (Houston). New opportunities do exist, although most seem to be niche markets rather than game-changers like synthetic turf infill and colored mulch. “The next big application like that isn’t readily apparent at this point,” Gray says. That said, major markets typically start as niche markets, and commanding a foothold in one or more of these markets could set tire recyclers up for success when a new product takes off.
Fashion forward
Although recycled tire rubber might seem an unlikely material for the fashion industry to use—rubber garments can be heavy, and they can trap heat and moisture—its use in sustainable fashion is on the rise as inventive businesses are making lighter recycled rubber materials.
Vulcana (Cranford, N.J.) incorporates at least 30% recycled postconsumer vehicle tires into its patented rubbRe fabric, “a non-woven sheet rubber type material.” It’s a thin, flexible, water- and scratch-resistant alternative to leather that the company says is Earth-friendly, animal-friendly, and human-friendly. A second product, füzun, is a sheet rubber material it makes by bonding rubbRe and a woven material, such as nylon or hemp. The rubber it uses has been devulcanized, compounded, calendared (spread into sheets), and cured. Vulcana’s third product, Re#, is a slab containing up to 50% recycled content that manufacturers can use to make compression-molded products.
Vulcana invented and patented its first formula in 1999 for use in handbags and accessories; in 2007 it began seeking new applications. The rubbRe product—available in a variety of colors, thicknesses, and textures—can bond to other fabrics and can be stitched with heavy-duty sewing equipment. Vulcana markets its products as appropriate for a wide range of applications, including purses, luggage, place mats, and jewelry. “Our goal is to continue to develop materials and uses for recycled car tires that meet the needs and demands of the commercial and industrial marketplace,” the company’s website states.
Shoes are another innovative area for the use of tire rubber in fashion, says Mary Sikora, publisher/editor of Scrap Tire News (Leesburg, Va.). Some people “think of old tire treads on the bottom of a sandal” when they imagine shoes made from scrap tires. That may have been the case early on, “but when you look online now at the different types of footwear, it’s really quite attractive,” making the products marketable to a wider audience, she says. She names Austin Rubber Co. (Austin, Texas) as one firm making devulcanized rubber, which they use for “beautiful sandals and different products that they sell under their trade name, Tredagain.” The sandals, sneakers, and boots have outsoles made from 50% recycled material.
Footwear company The Timberland Co. started incorporating crumb rubber from car and truck tires into its boot outsoles in 2008. “But we couldn’t guarantee the quality of the recycled rubber as our demand for the material increased,” its website states. In 2010, it switched to an outsole made of at least 35% postindustrial recycled latex. To move back to using postconsumer rubber, but also get the right material for its needs, in 2016 it partnered with tire manufacturer Omni United to design and manufacture a Timberland-branded car tire intended to have a second life as outsoles for Timberland shoes and boots.
Breaking the mold
Scrap tire end-use innovations occur not only when companies create entirely new markets for the material, but also when they enter markets that previously only consumed virgin rubber, Sikora says. One such market is molded rubber products. The traffic control and safety sector “uses quite a bit of recycled rubber,” including in traffic cones, Sikora says. “There are probably developments going on in that industry right now we may not know of—new products or applications of a product line.” Roofing is another market sector where recycled tire rubber is being substituted for virgin materials such as asphalt shingles. “If recycled rubber can go into those types of everyday products … that’s where you begin to build consistent end use and stable markets,” she says.
Ecore has experienced significant growth in another space previously dominated by virgin rubber: floor mats, underlays, and flooring tiles. Ecore took the “power of vulcanized rubber, which is a reclaimed material, and transformed it into a powerful base layer for other flooring,” Barber says. The sports and fitness industries traditionally have used rubber products in applications such as gym floor surfaces and underlays because of their impact-absorption qualities. Now Ecore is using that same premise to market its recycled rubber flooring underlays to hospitals and senior living facilities, where “falls are one of the biggest challenges of the industry,” Barber says. The tiles’ shock absorption also benefits health care workers who must stand and walk on the floors throughout the workday. “We’ve essentially … given nurses and patients a performance flooring designed for athletes,” Barber says. The rubber tiles absorb sound as well, reducing healthcare facility noise and creating a more peaceful environment for patients.
The tiles themselves are recyclable, and Ecore is capable of giving the material yet another life as a product, further increasing the material’s value. “The rubber itself is worth more per pound … in its second life as a tile than it was in its first life as a brand-new tire,” Barber says. “That’s the evolution of this industry.” Ecore has expanded its marketing to other industries that similarly could benefit from the recycled-content tiles. “That’s a success story,” Sikora says. “They have really grown a use case.”
Processing plays a part
Technology and equipment upgrades can help recyclers enter new scrap tire markets. Improved processing techniques produce higher quality materials—particularly “smaller and finer material,” Sikora says—that manufacturers can use in a wider variety of applications.
One such material is micronized rubber powder. MRP is nearly metal- and fiber-free, so it’s marketed for use in more advanced and higher value products than traditional crumb rubber. It commands a premium because of its performance characteristics, but it’s considered cheaper than incorporating virgin rubber into these applications. MRP industry leader Lehigh Technologies (Tucker, Ga.) says its MRP can cost up to 50% less than virgin rubber feedstocks.
Lehigh uses cryogenic processing capability to turn up to 50,000 mt of granulated scrap truck tire rubber a year into MRP. It freezes the tire chips with liquid nitrogen, which turns them into a brittle material similar to glass. A turbo impact mill shatters the frozen chips, and the resulting material is reheated, making a powder that resembles black flour. The individual particles range in size from approximately 20 mesh to 300 mesh, but “the majority of what comes out of our mill is 80 mesh or finer,” says Tom Rosenmayer, Lehigh Technologies’ chief technical officer.
“The biggest problem with cryo is it generates a bell-shaped curve of product sizes,” Gray says, which gives manufacturers the challenge of finding markets for all the different sizes one batch can produce. Recyclers could circulate larger material through the process a second time for further size reduction, but Lehigh says the economics of doing so don’t add up for its operations. The company prefers to stick with one pass and then “try to find a market for everything that comes through the process,” Rosenmayer says.
The market for MRP is still small. Lehigh’s 50,000 mt of tire rubber capacity is the equivalent of 4.4 million car tires a year. If the company were to operate at full capacity, it could process 1.7% of the scrap tire supply. “I haven’t heard a lot of growth in terms of 2019 MRP market volume, although the number of uses seems to be expanding,” says John Sheerin, director of end-of-life tire programs at USTMA. Michelin North America (Greenville, S.C.) finalized its acquisition of Lehigh Technologies last year, which has helped fuel its growth. The tire manufacturer uses MRP in its tires as a replacement for virgin feedstocks; its tires currently contain about 2% recycled materials, such as steel and rubber, it says. Michelin has the long-term goal of recycling all its tires and manufacturing its tires out of 80% sustainable materials by 2048.
Gray points out that cryogenic processing of crumb rubber has been around for decades but isn’t widely used because of the high operating costs. “The energy [needed] to create the liquid nitrogen is significant,” he says. “It’s a very good niche market,” but none of the businesses that tried it in the past “took over the world.” The formula for Lehigh’s success “is pretty simple,” Rosenmayer says—it’s scale. Other cryo operations aren’t as large or efficient, he says, and they don’t produce the material sizes needed to supply major markets, as Lehigh does with its 80 mesh MRP. Other companies are “using technologies that really produce a very small fraction of 80 mesh, or produce it slowly. We can produce a lot of it very quickly, which is our primary differentiator.”
Although Lehigh’s business primarily revolves around supplying the tire industry with material, it also participates in other markets, such as coatings and rubber-modified asphalt. Sikora anticipates further growth for MRP in the industrial, automotive, and construction coatings markets, where the product’s tiny particle size creates a smooth surface. Micronized rubber powder also mixes well with certain polymers to produce robust rubberized plastic blends. Lehigh has developed and patented thermoplastic elastomer technology that combines recycled rubber and elastomeric polymers and intends to delve into that market more extensively, Rosenmayer says.
Thermoplastic elastomers carry great potential for market expansion, industry participants say. “In the near future we’re going to be seeing some growth [in their use] in molded and extruded, or the plastics product category,” Sheerin says. When you blend fine crumb rubber with plastics, it makes a new material that can be “used in lieu of many plastic or elastomer parts,” he says. These hybrid-material parts have greater durability and prevent stress fractures better than wholly plastic products. For example, the auto industry leverages thermoplastic elastomer products to create more flexible auto parts that can withstand a greater impact. “And there’s a definite cost benefit,” Sheerin says.
Moving into the black
MRP often looks like, but should not be confused with, carbon black, which is a component extracted from scrap tires after thermal processing, most commonly through furnace combustion. Like cryogenic processing, scrap tire pyrolysis has been around for years, but thus far it hasn’t been viewed as an economically viable venture. Historically, the obstacle to the long-term sustainability of pyrolysis facilities “has not been the technology, but the ability to market the char, or carbon black, that comes from the process,” Gray says.
That tide may be turning, however, as a few new pyrolysis operations have launched recently, including the Pyrolyx USA facility in Terre Haute, Ind. The Munich-based Pyrolyx expects the new facility to process up to 4 million tires a year, which would have been 1.6% of the scrap tires the United States generated in 2017. It announced in late June that it expects to start production later this summer. Carbon black primarily is used as filler in tires, coatings, and inks, as well as plastic blends. Its ability to absorb ultraviolet light makes it valuable to reduce weathering and extend the life of products exposed to outdoor elements.
For Lehigh, the future involves a greater focus on material separation and contamination reduction through “intelligent deconstruction,” Rosenmayer says. The company wants to segregate all the different rubber compounds in a tire so customers can know exactly which material they’re purchasing and where it came from on a tire, such as the tread versus the sidewall. The concept has the potential to disrupt the tire recycling supply chain, he admits, which makes it “a tricky problem to solve … But we want to move in this direction because our customers see the utility of having better refined raw materials. It’s a strong future for us.”
Katie Pyzyk is a contributing writer for Scrap.
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Evaluating end markets
Finding viable end markets for scrap tire rubber is a challenge and an opportunity for recyclers, says John Sheerin, director of end-of-life tire programs at the U.S. Tire Manufacturers Association (Washington, D.C.), but as the scrap tire supply continues to grow, the need for markets will become even greater.
USTMA began a scrap tire program in 1990 “to incentivize uses for scrap tires and markets,” Sheerin says. It publishes a scrap tire management summary every two years. The most recent—
released in 2018 with data from 2017—shows that the United States generated about 256 million scrap tires in 2017, up 3.7% from 2015. The number of scrap tires that found their way to beneficial end-use markets continued to fall from its peak in 2013; 81% found a market in 2017, down from nearly 88% in 2015. However, “my expectation is that [the] trend has reversed, and we’re
going to see an uptick in the beneficial end-use rate in the next end market report … in part because of new and emerging technologies,” Sheerin says.
Pyrolysis, for example, is considered a growth market, evidenced by new businesses such as Pyrolyx (Terre Haute, Ind.) coming online this year. Pyrolyx anticipates consuming about 4 million tires annually, which is “greater than 1% of the market in just one example,” Sheerin says. Other manufacturers have announced plans to start pyrolysis operations in the United States as well. “As a result, we expect that in 2019’s market report, pyrolysis will be a greater-than-1% piece of the pie,” he says.
Tire-derived fuel continues to dominate scrap tire end use markets, as the destination for 43% of tires collected, but the number of tires that went into TDF decreased about 10% from 2015. TDF consumed about 1.7 million tons of scrap tires in 2017—down from 1.9 million—with cement kilns (46% of the market sector), pulp and paper mills (29%), and electric utility boilers (25%) constituting the bulk of the market. While TDF use at cement kilns increased 7% from 2015 to 2017, it fell at the latter two types of facilities 18% and 23%, respectively.
Ground rubber remains the No. 2 market for scrap tires, consuming 25% of those collected, about 1 million tons, down less than 1% from 2015. Top uses within that sector are molded and extruded products (38% of the market sector), playground and landscaping mulch (24%), sports surfaces (23%), and rubberized asphalt (12%). The use of recycled rubber infill in synthetic turf fields declined after 2014, when some groups raised concerns that the material might have negative health or environmental impacts, but the research to date has not supported those claims. “The synthetic turf market has seemingly recovered and is actually growing somewhat, not only in new field construction but also the refurbishment of old fields,” Sheerin says.
Civil engineering markets grew from about 275,000 tons of tires diverted in 2015 to 316,000 tons in 2017, a nearly 15% increase. Sheerin expects further growth in civil engineering applications and rubber-modified asphalt in the coming years.
This year USTMA released its inaugural sustainability report, which presents six sustainability visions. One aspirational vision is that all scrap tires enter sustainable end-use markets. It plans to release the sustainability report every other year.