What is Lyocell? Ancient Ideas Meet Modern Sustainability

Lyocell fiber has fairly rapidly grown in popularity across the commercial industry and the individual markets in the US across the last few decades. However, few seem to know much about this fascinating textile beyond vaguely understanding its vegan roots. Here we hope to dive a little deeper and bring into view some of the fascinating history, cleaner creation methods, and potential benefits of lyocell.

Ancient Roots to Modern Innovation: The Origin of TENCEL®

The oldest non-animal fabric in the world is estimated to be a 34,000-year-old linen remnant found in a cave in the Republic of Georgia, and hemp is not to be left behind with remnants found around to be 12,000 years old across Northern Asia where it was cultivated to make fabrics for garments, shoes, and even paper. Then there is cotton, found across the ancient globe- from Peru in 6000 BCE, to Mehrgarh, Pakistan in 5000 BCE, and in cultivation in the Indus Valley by 3300 BCE. Even now, cotton, hemp, and linen are forces to be reckoned with. even in the face of economics, droughts, and more. To say humans have been using plant fiber textiles for a while is an understatement.

So, if that's the case, what makes lyocell so different? Excellent question. Lyocell is the response to problems caused in response to problems within the earlier natural textile industry and is an improvement to the earlier, familiar semisynthetic- rayon. To understand what that means, we have to go back and take a quick peek into the how and why of rayon- the first building block to get to modern lyocell. 

For that, the first place to look is the French silk crisis of the 1860s. Disease tore through silkworms supplying French artisans making an already rare and delicate fabric even harder to supply. Naturally, this was a dramatic hit to the French silk industry and had begun to affect the French economy and so an effort by French scientists- led by Louis Pasteur and Count Hilaire de Chardonnet- to study the issue and save the industry began.

The idea, presumably conceived in part from scientific documentation based on an earlier theory from 1664 by English Naturalist Robert Hooke, to create an artificial silk was eventually conceived. Hooke theorized it was possible to create artificial silk filaments from wood pulp similar to the way silkworms produce silk.

By 1885 Chardonnet had patented the first successful method to manufacture cellulose into artificial silk (viscose), what would eventually become Rayon upon the Federal Trade Commission (FTC) coining the term to encompass any man-made fiber derived from cellulose. Time marched on and by 1955 Rayon production evolved and allowed for stronger and more versatile fabrics allowing for it to become one of the most widely used fabrics in the world. 

Sounds great, so what's the issue? In theory, rayon sounds fantastic as a semisynthetic fabric. It's breathable, absorbent, biodegradable, affordable, etc. Technically, lyocell is a type of rayon, but what most people tend to think of as rayon is viscose rayon and the issue is in the manufacturing. That's where lyocell and its creation come in. 

How it's Made: A Cleaner Spin on Semisynthetic Fiber

Undoubtedly, modern rayon is not the dangerous and environmentally disastrous methods used in the obsolete Bernigaut's method of 1884 (using both sulfuric and nitric acids to create the highly flammable nitrocellulose) or the Cuprammonium method of 1890 (combining cellulose with copper and ammonia or Tetraaminecopper (II) sulfate).  However, it still has a number of negatives to its process including large amounts of wastewater, the use of carbon disulfide which can seriously harm workers if mishandled, and an indirect solvent-regeneration route. 

Lyocell production, originally developed in 1972 in Enka, North Carolina by American Enka (no longer in operation), was studied at a pilot plant scale under the name "Newcell" using an organic solvent called NMMO. While they were unsuccessful in making this a commercialized process it was a clear start, and by 1981 the first description of this NMMO process to dissolve and reprecipitate cellulose was patented for Akzona Incorporated (holder for Akzo) and later licensed to Lenzing and Courtaulds. We'll come back to that, though. 

This new process allowed for much less water, got rid of carbon disulfide entirely, and worked on a closed loop that kept the environmental impact minimal. Instead of the cellulose being derivatized, NMMO allowed the cellulose to be dissolved directly and then reprecipitated in a water bath to produce a fiber. The closed loop means that the NMMO is recycled with 99% usually being recovered, and it biodegrades without producing harmful biproducts. So, while energy intensive and slightly more expensive, the process of making lyocell is overall more environmentally friendly and safer. 

Soft, Strong, and Sustainable: The Benefits of Lyocell Fibers

Coming back to the licensing of the NMMO method of producing lyocell fiber; you may or may not recognize the name Lenzing, but you will likely recognize their branding if you're familiar with lyocell yarn, fiber, or fabric. Lenzing is the owner of the brand TENCEL®, the genericization often used to refer to lyocell. So, if you were unsure before this is one and the same. 

Vegan, 50% more absorbent than cotton, breathable, long and smooth fibers that lend to a silky feel- all the benefits you know and love about TENCEL® are all things that you now know that you love about lyocell. Lyocell fibers are also easy to blend with other staple fibers resulting in a new fabric that is more wear resistant, resistant to pilling, and stronger.  

Practically speaking, these fibers also take on dyes well- typically needing less than a comparable cotton to achieve similar vibrance, are usually machine washable or dry cleanable, and can be made in a variety of desired finishes. Future research is even exploring their use in the medical field by looking at ways to add antibacterial properties to enhance the already low-toxicity, comfortable, biodegradable fabric for use as surgical dressings, scrubs, lab coats, and more!

Finally, we already know that the manufacturing is lower environmental impact and that lyocell, like all rayons, is biodegradable. But are there any other sustainability or eco-friendly benefits? Actually, yes. Because like rayon (viscose) it can use actual woody plants to produce cellulose, most believe it would be a deforestation concern. However, sustainable, reputable sources of lyocell like TENCEL® prefer to source from fast-growing wood sources like bamboo, eucalyptus, and spruce to maintain renewability. 

Lyocell at Meridian Mill House™

Time to wrap it all up with a neat little bow: humans have been using plants to fix our textile problems ever since the first one realized we could smash one up and turn it into threads. Modern humans aren't any different; we just take a more modern approach to the same problems and that's okay. Sometimes the oldest answers still have some wisdom for us- from ancient Georgia and Peru to Robert Hooke and Count Hilaire de Chardonnet, all the way to North Carolina in 1972 and Denmark in 1981. 

So, why did we decide to carry lyocell fiber here at the Mill House? I had a few guesses, but I decided to reach out directly to our Director of Sales and our VP of Sales to get it straight from the horses' mouth if you will. Stephen and Hannah, fabulous as always, were happy to help.

As it turns out, they were looking for something new to add in to the offerings of the growing Mill House brand. Lyocell, they said, was an "environmentally responsible, closed loop process... biodegradable, making it an eco-friendly option." Stephen also cited that it was an ideal warp yarn as the fibers are soft, smooth, and tend to be stronger than cotton. Finally, I was told they also liked the luster of lyocell yarns and how easily they take and retain dyes for vibrant color. 

 There you have it. The story of lyocell fiber and why lyocell came to the Mill House. I tried to hit the highlights without turning it into a term paper, but still. This was a long one this month, y'all. Thanks for sticking with me. As always, we appreciate your thoughts, questions, or requests for topics. See you next month!