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The Future of Recycled Cotton Denim Leans on Innovation

Everything old is new again, at least where the denim industry is concerned. Mills are churning out fabrics made from castoff clothing and brands and retailers are relishing these so-called “recycled” jeans as they move from niche to norm.

All this buzz is thrilling to the Alliance for Responsible Denim, an initiative based out of the Amsterdam University of Applied Sciences, which works to mitigate the environmental impact of the denim industry. Instead of being relegated to a small rack in the back of a room, recycled styles are now “front and center” in the conversation about sustainability, said Hélène Smits, initiator and lead of the Circle Textiles program at Circle Economy, one of the organizations involved in the alliance.

Kilim, Orta and Tavex are members of the small but growing fraternity, as are the Arcadia Group, Asos, Gap, Nudie Jeans and Mud Jeans. All of these companies see the “need to make denim more sustainable, and they want to be a part of that,” Smits said.

Denim, as many critics have noted, is a filthy, dirty business. Just growing the cotton that goes into a pair of Levi’s 501 jeans consumes about 2,570 liters of water, according to a life-cycle assessment by the denim giant. That’s seven times more than fabric production, cutting, sewing, and finishing combined. Replacing 20 percent of the cotton in denim with fibers from post-consumer sources, on the other hand, can save up to 500 liters per garment, Smits said.

“There’s a lot of innovation in the dyeing process and in the finishing process, which is great,” she said. “But those water and chemical savings are only a small percentage of the savings you get by using recycled material.”

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Indeed, a 2016 study commissioned by H&M found that employing recycled cotton “for the stages up to when the fiber is ready for spinning” reduces climate and water impacts by up to 90 percent.

Made-By, a European fashion not-for-profit that has partnered with the Alliance for Responsible Denim, rated recycled cotton more highly than even organic cotton in its environmental benchmark for fibers. Besides requiring less energy, water and land, as well as fewer chemicals than its virgin counterpart, recycled cotton also generates fewer greenhouse-gas emissions during production.

Using reclaimed materials tackles an additional problem: the prodigious volume of textile waste that ends up in the landfill or incinerator. Americans alone toss aside 13 million tons of textiles—about 310,000 truck-loads’ worth—every year, according to Secondary Materials and Recycled Textiles, an international trade association for companies that sort post-consumer textiles for recycling. “These textiles are valuable materials that can be used again,” Smit said.

Overcoming obstacles

There are limitations to using recycled cotton, of course. For one thing, it costs more. Amassing used clothing, then combing through a sea of polyester and rayon blends is labor-intensive work. (Some mills prefer to collect only secondhand jeans for this reason). So is the process of mechanically chopping up garments into pulp for spinning.

Plus, mills have caps on how much recycled cotton they can use. Because the shredding process reduces the fiber’s staple length, which can weaken the integrity of the resulting fabric, manufacturers have to bolster the recycled cotton slurry with other, stronger fibers—virgin cotton, say, or in the case of Lindex’s Even Better Denim, a mix of virgin cotton and polyester derived from post-consumer recycled plastic bottles.

“Right now, it’s only possible to have a maximum 20 percent of the garment in post-consumer recycled cotton,” said Anna-Karin Dahlberg, Lindex corporate sustainability manager. “After that, the fibers get too short and the quality of the fabric will be inferior and it will rip easily.”

The provenance, and chemical composition, of other people’s throwaways can also complicate matters. “You don’t really know where the denim comes from,” Dahlberg said. “And they could come from a country or brand where the legislation of chemical content is not as tough as the one that we follow.”

Next steps

Potential contamination is why mills like Candiani in Italy opt to use pre-consumer fibers, their own cutting-floor scraps among them, in their recycled denim. Candiani works with Lenzing to blend its recycled cotton with Refibra, a type of Tencel that the Austrian fiber manufacturer creates using cellulose and post-industrial cotton waste.

Lenzing makes Refibra using a closed-loop chemical process, a tack the company says neither compromises fiber strength nor limits the amount of recycled content.

Candiani’s Re-Gen denim, for instance, comprises 50 percent Refibra and 50 percent pre-consumer recycled cotton in both its warp and weft. “There is no fresh, raw cotton woven into this denim,” said Marykate Kelley, the mill’s marketing manager.

H&M is another company eager to overcome mechanical recycling’s constraints. The retailer has partnered with the Hong Kong Research Institute of Textiles and Apparel to develop a way of recycling blended textiles into new fabrics and yarns without any loss in quality. It has also tapped Re:newcell, a firm that dissolves waste cotton and viscose into high-quality raw materials, for future collaborations.

“So even if there are challenges, we see great innovation breakthroughs,” said Cecilia Strömblad Brännsten, acting environmental sustainability manager at H&M.

As talk of a “circular economy,” where products are made to be reused and recycled rather than thrown away, grows more vociferous, the spotlight on recycled denim has also become brighter.

Mud Jeans, for one, has crafted a business model based on selling jeans, taking them back at the end of their life, and then recycling those old jeans into new ones. Through trial and error, the company has honed its logistics to an art.

Still, the brand is keen to increase the proportion of recycled cotton it uses per garment—40 percent, which is higher than the industry average. It’s hopeful, though.

“We’re just starting to come to a tipping point where we get economies of scale,” said Dion Vijgeboom, co-owner of Mud Jeans. “So, we’re getting to the point where it’s becoming interesting to work like this.