The Life Cycle of Tencel

Recently, the two of us at Soluna Collective, decided to use Tencel in our new clothing line. We did it because the voices on the internet told us that “Tencel is a sustainable fiber...” and we believed them. We received results from brands, bloggers, journalist, influencers and anyone in-between presenting facts and figures about the sustainability of the fiber.. However, what we didn’t see, were sources to hard evidence that we could follow and judge the facts for ourselves. So we decided to create this page. The goal was simple: be helpful. Be helpful to anyone that wants dig a little deeper and provide sources to all data (in many cases original sources). We wanted to discuss the good, the bad, the unknown and we didn’t want to be afraid of showing all the facts. Hopefully we did that.

We created a short and long version. The short is just what you see as you scroll the page. The long is accessible by clicking on the images and text. It’s there you will see the full story and links to learn more.




Just A Quick History



Rayon: A textile fiber or fabric made from regenerated cellulose.



Types of Rayon






Inputs

Making of Tencel

Wood

Most of the wood used in Lenzing’s Tencel production is derived from eucalyptus (South Africa), beech (Europe), pine (USA), birch (Europe) and spruce (Europe) trees. All wood is sourced from FSC or PEFC certified forests/semi-forests/plantations.

Wood is a fantastic renewable resource that Lenzing also uses to fuel their Austria and Czech Republic plants. If sourced correctly, minimal environmental concerns exist. The major concerns would be the effects of groundwater usage and depletion of soil nutrients on natural ecosystems.

Wood Chipping

Once cut, the logs are transported to a wood chipping facility and chopped into small pieces. These pieces are then transported to a pulp facility for further processing. Some pulp facilities will have the wood chipping process done on-site.

Pulp Production

The wood chips are placed in a solution of water, caustic soda (using mercury free technology) and sodium sulfide. An elemental chlorine free (ECF) or totally chlorine free (TCF) bleaching process is used. Both are considered to have a low environmental impact. One of the biggest environmental concerns with pulp production is the energy demand. Lenzing overcomes this by having their own pulp production facilities that use 100% renewable energy. However, only about 50% of all pulp comes from Lenzing facilities while the other 50% is externally sourced. I would consider pulp production the biggest concern from an environmental standpoint.

NMMO Solution

This is where the magic happens. A little science (NMMO) turns the wood pulp into a regenerated cellulose fiber called lyocell. NMMO is the only chemical solent needed and the compound itself and effluent are considered non-toxic. The best part about the NMMO solution is that 99% of it can be recycled and used again!

Spinnet

The solution is pushed through small holes and the fiber starts to form.

One Last Spray

This is again water and NMMO. It helps strengthen the fiber.

Enzyme Treatment

To help with pilling and fuzz, a simple enzyme treatment is used. This gives the end fabric a softer and more peach-skin feel.

Finishing Touch

The fibers are spun into yarn or thread for final production. They can be spun with other materials as well.

Wood

Wood Chipping

Pulp Production

NMMO Solution

Spinnet

One Last Spray

Enzyme Treatment

Finishing Touch







Biodegradability
of Lyocell








Environmental
Impact

  • Pros

  • Cons


Pros

  • 99% Recyclable The NMMO solution is 99% recyclable which keeps chemicals out of the landfills and aquatic systems.

    The Remaining 1% The 1% remaining effluent from the NMMO solution is easily broken down using a biological wastewater treatment.

    Renewable Resource When done correctly, the sourcing of wood can be a replenishable resource. The logging process at Lenzing is certified by either FSC or PEFC. This prevents deforestation and harmful impacts on local ecosystems.

    Less Water Lenzing claims “Lyocell technology only requires one third of the process water needed in viscose technology.” It also uses less than cotton.

    Water Footprint No matter the production process for Lenzing’s Tencel, the overall water footprint was better compared to both conventional cotton and polyester. Tencel produced at Lenzing’s state of the art facility provided the best water footprint.

    Energy Use Lyocell production is extremely energy intensive. However, Lenzing’s facility is almost entirely run by renewable resources. Specifically, wood pulp.

    Less Laundry Lyocell holds anti-bacterial properties which should lead to fewer washes. This can potentially give lyocell huge water and energy savings over its lifecycle.

    100% Biodegradable/Compostable Enough said.

    Increased Tensile Strength Because of its high crystalline structure, Tencel has a higher tensile strength when dry and wet compared cotton and other regenerated cellulose fibers.

    Emission Savings Tencel production provides a greenhouse gas saving of about 1.5-5 times compared to cotton. At best is can save about 15-21 tonnes of CO2 per hectare.


  • Cons

  • Needs Water While Tencel does use less water and the overall water footprint is better compared to other fibers, it still uses a good amount of water.

    Deforestation While in Lenzing’s production of lyocell, deforestation impacts seem to be minimal, it should be worth noting that deforestation can cause major environmental harm. Look for the brands/companies doing it right! I would also add that we need to continue to verify and improve certifications.

    Eco-systems Even when done right, the cutting down of trees of any type for mass production will cause distribution to natural ecosystems.

    Energy Usage The pulp production process is extremely energy intensive. While Lenzing’s facilities are run on almost all renewable energy, the 50% of the pulp they obtain from other factories are not. This can be improved as renewable energy becomes more widely used.

    Land Usage This really depends on the climate and area where trees are grown. If topsoil is preserved, I see the impact as minimal.

    Chemicals As with most fiber production, chemicals used during the process can cause environmental problems. For Tencel, caustic soda and sodium sulfide, which are used in pulp production are of concern. Environmental impact seem minimal but precaution to wastewater treatment is a necessity.

    Pulp Production As you can see from the other cons, pulp production is energy demanding, uses a lot of water and can be chemically intensive.

    Dyeability Because lyocell has less surface energy, it does not take dyes easily. At times, more chemically intensive dyes are needed to dye the fabric. The problem can be solved by using GOTS or Oeko-Tex certified dyes.



The Future

Final Thoughts

We like to imagine sustainable fashion as being 100% sustainable. However, it never really works like that. When creating and using any piece of fashion in this world, large amounts of energy, water and resources are needed. Honestly, nothing in fashion can truly be 100% sustainable. While that might seem to contradict to the term “sustainable fashion”, I find it as more of a guideline. I see it as: when we create fashion, we create it with the purpose of being conscious of the environment. At all stages in production, we strive to use resources that provide the least amount of harm to the planet and the people living on it. While that has many applications to different brands, consumers and environmentalist, I see it as a great starting point.

While I want to leave the question “Is Tencel Sustainable” up to you to judge... For the two of us at Soluna Collective, Tencel will be part of our fabric mix now and into the future. It will not be the only fabric but it will be a part of our diverse mix!