The Life Cycle of Tencel

Just A Quick History

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  Birth of Rayon (1855)

  Swiss chemist, George Audemars was the first to patent artificially derived cellulose fiber from mulberry trees. It was given the name Rayon.

  

  Birth of Rayon (1855)

  Probably the most famous chemist when it comes to the history of rayon fibers is, Georges Audemars. His groundbreaking patent describes the entire process in which to obtain a regenerated cellulose fiber. That fiber will later be known as rayon. I want to give you the basic steps of his process as they are the building blocks to everything to come.

  • Boil the bark from mulberry trees in water in order to separate the inner bark. The inner bark will become the soon to be fiber.
  • Create a pulp from the inner bark using carbonate soda, soap and nitric acid.
  • Soak that pulp in an ammonia-alcohol solution and bleach it with chloride of lime.
  • A end fiber is created. This fiber can be “hackled, combed or carded and then spun like cotton”.

  He mentions the ability to use this end fiber for photographic purposes by converting it to an “explosive compound” and doing some more chemistry. He also recognizes the fiber as a substitute for silk.

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  A Solution (1966-69)

  In 1966, D. L. Johnson of Eastman Kodak Inc. patents the first cellulose fiber made with NMMO. NMMO is the primary chemical in lyocell.

  

  Finding A Solution (1966-69)

  The chemical solution for lyocell was first patented by Dee Lynn Johnson. He was experimenting with different acetate solutions in order to find a cheaper film alternative for Eastman Kodak. In the process, he found that dissolving cellulose in amine oxide would strengthen paper. The 1969 patent claims, the “highly preferred” amine oxide is, “cyclic mono(N-methylamine-N-Oxide) compound” or NMMO. He also claims an increased wet and dry tensile strength when certain anime oxides (including NMMO) are used. NMMO is also part of the process to dissolve blended cotton/polyester fabrics for reuse.

• 

  So Close (1969-79)

  American Enka, a U.S. company, develops the first functional lyocell fibers. However, they fail to commercialize it.

  

  So Close (1969-79)

  Neil Franks and Julianna Varga of American Enka created a process to derive “higher concentrations of cellulose” in an amine oxide solution. In the end, this new solution made the process more economically friendly as it increased the amount of fiber per batch. Another chemist at American Enka, Clarence C McCorsley III developed the commercial potential further by finding a way to feed the solution (dope) through an extruder. This made it possible to spin it into a yarn. American Enka would stop research in 1981 due to engineering concerns and economic viability. They will return to the lyocell race later but as part of Akzo Nobel.

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  Production (1982-1998)

  Pat White of Courtaulds, commercializes lyocell production 1982 and they label it Tencel! Court battles with an Austrian company named Lenzing proceed.

  

  Tencel + Production (2004-Present)

  Patrick White’s R&D team at Courtaulds was the first to fully commercialize lyocell in 1982 and reach production capacity in 1992. Courtaulds is also credited with pioneer the famous trademark name Tencel in 1990. Courtaulds developed two production plants for the fiber, one in Grimsby, England and the other in Mobile, Alabama.

  Around this time, the Austrian company Lenzing starts to patent lyocell technology and production processes similar to Courtlauds. The two companies proceed into lengthy court battles of around 690 patents. It would cost both sides tremendously with one estimate of around 5-10 million pounds (in mostly legal fees) for Courtaulds. The entire court battle is a little confusing but in the end, both companies reached an agreement to share the patent rights royalty free. Lastly, in 1998, Courtaulds was acquired by Akzo Nobel in a move for dominance of the paint and coating sector. It received Tencel in the process.

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  Lenzing (2004-Present)

  Lenzing buys the rights to Tencel and is currently one of the largest producers of lyocell in the world. They are also known for their sustainable production processes.

  

  Lenzing Buys Tencel (2004-Present)

  From 1998 to 2004, nothing really came of Tencel or lyocell for that matter. Akzo sold the rights to Tencel to CVC Capital Partners in 2000 and Lenzing was struggling to increase lyocell’s market share. However, what transcribed in 2001 would in my eyes, decide Tencel’s fate. In 2001, the courts of the European Union denied CVC’s acquisition of Lenzing due to antitrust issues. Instead B&C Privatstiftung, funded by the Bank of Austria, bought (and currently holds) a majority share in Lenzing. The purpose of the holding was to invest in Austrian owned businesses. With the new cash infusion, Lenzing flipped the script and bought the trade name Tencel from Corsadi BV, a subsidiary of CVC, in 2004. Might seem weird but if you read the case from CVC’s potential buyout of Lenzing, you will see that lyocell had nothing to do with the EU’s antitrust decision. In the acquisition of Tencel, Lenzing also acquired both the Grimsby and Mobile plants, which had cumulative production capacities of roughly 80,000 tons of lyocell annually. Lenzing’s Heilgenkreuz plant only totalled 40,000 tons at that time.

  Jumping forward to the present, Lenzing is by far the leading lyocell producer in the world. In 2017, Lezning’s Heilgenkreuz plant announced that is would increase its production capacity by 25,000 tons. It still has the plants in Grimsby and Mobile with latest production capacities of 45,000 and 51,000 tons for Tencel, respectively. It also plans to finish production in 2020 on a new state-of-the-art Tencel facility in Prachinburi, Thailand. The plant will have a production capacity of 100,000 tons.

Types of Rayon

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  Viscose

  Viscose was created in 1894 as a form of artificial silk. It's probably the most well-known form of Rayon.

  

  Viscose

  Viscose is the most common form of rayon and often used as a synonym for rayon. It’s mainly derived from hardwood trees such as, beech, spruce and eucalyptus. The end fiber is considered 100% biodegradable. A few of the major environmental concerns with viscose include deforestation, chlorine bleach treatment, water usage/footprint and air emissions from carbon disulphide (CS2).

  • Deforestation can be minimized by sourcing trees from semi-forests or plantations that hold certifications such as FSC and PEFC. Currently, there are 120 million trees being cut down annually for viscose production.
  • Chlorine treatment, which we will discuss in depth later, can be partially mitigated by using TCF or ECF treatments.
  • Water usage is considered to be high and varies a lot. However, overall water footprint is significantly less compared to both polyester and conventional cotton.

  One of the main chemicals needed to produce viscose is CS2. During the viscose production process, CS2 emits sulphur compounds which are hazardous to the environment. The exact amount air emissions is not well known but emissions do increase significantly with the amount of CS2 used. Companies like Lenzing, have invested in air filtration systems that curb the amount of CS2 released into the atmosphere. Unfortunately, it does not seem that we can currently capture 100% of the CS2 emissions.

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  Lyocell/Tencel

  To make things easy, Tencel is lyocell but Tencel is patented by Lenzing.

  

  Lyocell/Tencel

  We will talk about this below.

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  Modal

  Beech trees are the main derivative in modal. Mostly used in household items like towels, bedsheets and upholstery.

  

  Modal

  Modal has an identical process to viscose (see viscose) with the major difference being the amount of CS2 needed. Once again, the amount really depends on the production size but one study estimates the amount of CS2 needed for modal is around 10-20% higher compared to viscose. Remember, CS2 emits sulphur compounds during the production process which are hazardous to the environment. The exact air emissions are not well known but depend on the amount of CS2 used and the ability to capture those CS2 emissions at the production site.

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  Cupro

  The process has been around for awhile (early 1900's) but it only recently took off in the textile sector. Feels like a heavier silk.

  

  Cuprammonium (Cupro)

  Cupro or Cuprammonium Rayon is a complicated fabric from a sustainability standpoint. It’s made using cotton linter but don’t get that confused with cotton lint. Many call this a by-product of the cotton industry, which is not wrong, but not necessarily accurate either. It’s still cotton. Like all rayon, cupro is 100% biodegradable!

  According to Asahi Kasei, the leading producer of cupro, 99.8% of the waste created during the production of their cupro is recyclable. That waste is used to power their factory through incineration. I should note, about 40% of the energy needed to power Asahi’s plants comes from renewable resources, while the remaining comes from mostly coal and natural gas... which is a great start.

  Now, here’s the confusing stuff. While the process might be nearly 100% zero waste, it’s not closed looped. I don’t see this as a negative but instead, an important distinction for what follows. Since the chemical solution cannot be reused, it’s either incinerated or deemed a waste. I am not sure if a closed loop process is possible for cupro but Asahi Kasei does not claim such.

  Now for that small amount (0.2%) of waste. While the environmental impact of cupro’s waste is a contentious topic, my understanding is that when treated correctly, the waste is considered to have a low environmental impact. However, the treatment of this waste (again a contentious topic), has been considered by some to not be economically feasible. In 1996, the United States government stopped the production of cupro due to the “cost of cleaning waste water to meet clean water standards”. The European Union and Japan (where Asahi Kasei is located) do not have such bans and treat cupro wastewater.

  With so little waste coming from Asahi’s process, I don’t see any major environmental concerns with Asahi's process. I do not hold the same opinion with other companies cupro production processes. Laslty, I would love to see more research into the environmental profile and water footprint of cupro!

  
  

Lyocell Inputs

Making of Tencel