If not viscose for sustainable fabric, then what?

«Creating new technologies to overcome the obvious environmental degradation in conventional viscose production», suggests Peter Bartsch, the sustainability director at Lenzing

With demand for textiles increasing and regular technological innovations, the landscape of fashion is changing, yet attempts to move towards more environmentally sustainable materials can have drawbacks. Viscose, a biodegradable, ‘eco-friendly’ textile sourced from hardwood, has recently had its sustainability re-evaluated. It is estimated that 120 million trees are cut down each year for viscose production, often from ancient and endangered forests. This logging can impact ecosystems as they are degraded and destroyed, and non-indigenous trees are used to replace those that are felled. During the cultivation of the forests, chemicals used in pest control and fertilization, soil erosion, degradation of water quality and deforestation can impact the local hydrological patterns. Textile development companies are now looking to find other ways to improve their ‘sustainable’ fabrics.

Viscose is a cellulose-based fiber sourced from wood forests and plantations. It has a variety of applications, from clothing textiles to industrial uses. As a raw material, wood exists within a natural circle as the cellulose fiber can find its way into the ground as it breaks down. In production, trees from forests or plantations are harvested, peeled, and cut into logs transported to a mill to be debarked. The logs are then processed to break them down into wood pulp and further transformed into viscose filament yarns or staple fibers. Wood logs are reduced to chips to go through chemical pulping, which involves the purification and separation of the wood fibers. The brown pulp produced is then washed and cleaned through caustic extraction to increase its purity. Caustic extraction used to be polluting as its run off would be released into watercourses; now, it is more likely to be recovered for energy production, evaporated, and burned to generate steam. After cleaning and washing, the pulp is bleached with chemicals that cannot be recovered. In viscose production, the pulp is treated with carbon disulfide and dissolved by adding a sodium hydroxide solution. This process has the potential for chemical runoff, which can cause pollution of local land and water sources. The solution is then turned into fiber strings by forcing liquid through a spinneret and into an acid bath where the acid coagulates and solidifies the filaments to spin into a yarn. These fibers require bleaching before they are dyed.

Each of these production steps requires high energy and chemical inputs, contributing to significant air and water emissions. However, there are ways to overcome the environmental issues at the production level by altering the chemicals used at each step (or making them a closed loop) and sustainable logging practices. Lenzing, a company with 80 years’ experience, has been providing innovation in the field to reduce the environmental impact of viscose. Peter Bartsch, the sustainability director at Lenzing, explained how their journey to creating environmentally sustainable fibers began in the Seventies «when people did not seem to care as much about the environment». Despite Lenzing already producing viscose in the aforementioned ‘traditional’ manner, the company realized that environmental problems were becoming severe. «We had to decide what to do, and so the team focused their energies on becoming more sustainable through innovation and created new technologies to overcome the obvious environmental degradation that was taking place». In altering their technologies, they have managed to change their mindset to become environmentally focused. Nearly 50 years later, Lenzing has nearly closed their loop, allowing them to use just under 100 percent of the wood input through bio-refinery, and reuse the solvents used in processing. This closing of the textile loop and high recovery rate, allows for environmental benefits and reduces costs throughout each production stage. This dispels the concept that being environmentally sustainable comes with a higher price tag. 

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Using waste wood products and recycled materials helps Lenzing meet their carbon neutrality aims as they do not have to rely on fossil fuels to power their production or create a new textile

In attempting to close the production loop, Lenzing has adapted its production methods to allow for most of the input material to be used (and reduce waste products). «About 40 percent of the wood is cellulose, which is used in our fiber production. The other 60 percent can be used to extract valuable co-products that we sell into other industries, processes that we can do on-site. For example, we can produce acetic acid, which is bio-based and can be sold into the chemical and food industries. We can sell these co-products, and the rest of the wood material can be used for energy production». This concept of bio-refinery, extracting all valuable products from the raw material, acts as a «building block to achieving our target of 50 percent recycled content by 2024. It acts as a link between using all our raw material and  recycling textile waste to make new fibers. We use bio-refinery to create a blended product with 30 percent recycled content». Using waste wood products and recycled materials helps Lenzing meet their carbon neutrality aims as they do not have to rely on fossil fuels to power their production or create a new textile. One of the main concerns with viscose production is with respect to the chemicals used at each step. However, Lenzing has developed their viscose technologies so as to allow for the reuse of chemicals, an ongoing process that they have modeled on their lyocell technology, which reuses 99.7 percent of the solvent. Bartsch does not believe that it is possible to achieve 100 percent reuse as this would require «too much energy, which would then outweigh any potential environmental benefits». The process of achieving environmental sustainability requires meeting the needs of People, the Planet, and Profit in a holistic approach that meets the needs of all involved in the value chain.

Lenzing’s aims towards environmental sustainability go beyond the production process; instead, they believe that they need to start at the root; their wood supply. «Our sourcing starts with internal management and regulations that are in place within the company; we have a strict wood and pulp sourcing policy. We do not source our wood from regions that are deemed critically endangered forests». Lenzing ensures that their wood comes from worldwide sustainably managed forests that are cleared with the leading forest certification schemes such as FSC® and PEFC™, which encourage farmers’ level of protection. This ensures that they can keep track of the footprint of their raw materials. They carry out both internal and external audits to regularly check their and their suppliers’ performance. «We have also been working alongside Canadian NGO Canopy who have an ongoing initiative roadmap» and encourage complete transparency in sourcing. Lenzing believes that this level of care for forests is important as «We all need wood for building, leisure, clothing, so it is important that we do not allow this resource to deplete. By sourcing from sustainably managed forests, we are making sure that there are enough resources for future generations». They are in a position where they can influence the future of viscose.

Bartsch believes that «our responsibility is to design the most sustainable processes ». Doing this requires communication and transparency between all involved in the value chain throughout the different steps. In attempting to do this, Lenzing ensures that they maintain communication between all involved; «we have talked to our customers, NGOs, local people and investors to understand what everyone is expecting and needing. We then looked into our business model to best align all of these needs». Lenzing’s relationships are based on trust from direct customers, developers, and designers as «they need to know what is behind each product». Their regular communication with all parties involved means that they can understand where each production component comes from and ends its life. To track this, they use Fibercoin technology, «which allows us to track from start to finish, tracing the fiber, yarn, and garment stages. This means that our customers and we can know where everything comes from. It also allows us to track the quality of our fibers so that our customers can be provided with the product that they are accustomed to».

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PT. South Pacific Viscose (Purwakarta site), PT. South Pacific Viscose, Image Qubic, Courtesy Lenzing

There are eco-responsible ways to produce viscose, and according to the Hot Button Report 2020, the fiber sourcing analysis tool, Lenzing for the first time achieves the highest Hot Button category – innovative by nature. Lenzing has developed its viscose products, keeping environmental sustainability at the forefront of their innovations, and transparently closing the fiber production loop. Bartsch states that they will continue to provide technological development within this field to «continue to reduce our CO2 footprint», by understanding how their products fit within the textile value chain. Lenzing acts as a pioneer for streamlining a circular value chain. Technological developments are a continuous challenge; «we will be continuously improving on existing technologies and products as stakeholder needs are constantly developing». In order to successfully ‘close the loop’ and reduce their environmental footprint, Lenzing will «need to team up with all parties involved across the viscose value chain in order to provide suitable raw materials and to source these sustainably. Each aspect of our production involves its own environmental footprint so, to be sustainable, we need to make sure that each step, and each product we use, will be carbon neutral».


Lenzing Aktiengesellschaft
4860 Lenzing, AustriaWerkstraße 2
[email protected]

The writer does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article.