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I sleep on a lot of bedding. It comes with the territory when you test bed sheets and comforters for a living. I've slept on everything from bamboo and silk to plain-weave cotton, but there's a term I've seen quite often in bedding materials that I didn't know much about: lyocell. So I had to know. What makes it different from other bedding materials? Is it more comfortable to sleep on? Are the cooling and eco-conscious descriptions I often saw accurate? What's Tencel, and is it different from lyocell?
Lyocell is a cellulose-based, man-made fiber similar to fabrics like rayon with purported eco-friendly benefits in the manner it's manufactured. Is it the magic solution to eco-friendly sheets? No. But it's a move in the right direction, and there's plenty of opportunity for lyocell to become an even more eco-conscious choice.
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Close the Loop
Lyocell has a cellulose structure, similar to both rayon and cotton, so it isn't a synthetic fabric. But while we harvest cotton from a plant, lyocell and rayon are man-made fibers that take wood pulp and transform it into a fiber and eventually fabric. “The process is called wet spinning,” says Karen Leonas, a professor of textile sciences at the Wilson College of Textiles at North Carolina State University. “It takes wood pulp and makes a slurry, and then makes it into a filament, then into a fiber.”
The process for the two is different enough that rayon and lyocell are labeled by the Federal Trade Commission as separate fibers. One of the biggest differences is output. Making rayon uses different, harsher chemicals that can't be reused, while lyocell is known for its closed-loop production processes that reuse almost all of the solvent to make more lyocell.
Leonas says lyocell is a better choice than rayon because of the different chemical choices in its manufacture. Namely, she says rayon production uses carbon disulfide, which is toxic to both the environment and the people working on the wet spinning process. Lyocell production does not. “There are solid found technical reasons from the chemical point of view that make it more environmentally friendly and less toxic to workers,” she says.
The words Tencel and lyocell are often used together, or sometimes interchangeably. Where lyocell is the fabric, Tencel is the brand. It's owned by the Lenzing Group, which makes a specific trademarked Tencel Lyocell fabric. “It's like cornflakes versus Kellogg's,” Leonas says. You can find lyocell in all kinds of bedding, from sheets to our favorite mattress.
The upside of a branded lyocell like Tencel is knowing more details about the process. Tencel has a few different efforts to be more eco-conscious in its manufacturing. Lenzing's senior business development manager Walter Bridgham confirmed that the company uses a closed-loop process at Lenzing and that “more than 99.8 percent of the solvent is recovered and fed back into the loop, resulting in close to zero wastage."
Raw Problem
But there's another cost to the environment when making these (or any) fabrics: the materials needed. Standard rayon contributes to deforestation, as the wood required often isn't sustainably harvested. Bridgham says Tencel uses wood sourced from certified origins meeting standards set by either the US Forest Steward Council or the European Programme for the Endorsement of Forest Certification. “The wood taken from nature is purposefully balanced with forest growth rates, to ensure the continued availability of this valuable resource,” Bridgham says.
Nicole Rycroft, the executive director of CanopyPlanet, a nonprofit that helps companies adjust their supply chain choices to better protect forests, confirmed that Lenzing practices what it preaches. “They have been audited and taken steps to eliminate and reduce the risk that sourcing from high biodiversity forests,” she says. But that doesn't mean every lyocell you see out there follows these practices.
Rycroft says it isn't enough. She says Lenzing, and other textile makers, needs to diversify that fiber basket and use fibers that would otherwise go to the landfill. Lenzing is working on something along those lines. Its Refibra line uses the lyocell process, but rather than use cellulose from trees it uses recycled cotton and cotton waste from postproduction “It's very exciting, because it goes into the circular economy and diverts materials from the landfill and replaces the raw materials,” Leonas says.
Unfortunately, it's expensive to manufacture. Refibra also only promises to use up to 20 percent recycled materials, so it's not a perfect solution either.
“It’s expensive to be sustainable,” Leonas says. “It costs money to put conditions in place that aren’t going to harm people and respect the environment."
