Viscose rayon is a mystifying textile: it goes by several different names and is often marketed as eco-friendly, but it has a checkered past (and present). So there remains a critical question for the fashion industry – is a more sustainable alternative even possible at scale?
Last week at the Future Fabrics expo in London, among several new alternatives, two textiles were put forward as the potential next generation of viscose.
Every year, 300m trees are felled to produce viscose rayon, according to environmental not-for-profit group Canopy.
In April, Canopy was awarded a $60m grant by The Audacious Project (a Ted Talks-aligned funding initiative) to accelerate the commercialisation of next-generation viscose made from cotton waste, coconut water, citrus fruit, wheat straw, corn, molasses and hemp.
The Canopy founder, Nicole Rycroft, says their aim is to work with businesses to get 60m tonnes of new materials on the market by 2033. She says they have to be focused on “bold levels of change” to transform the pulp sector (which spans paper and packaging too) because the “fastest, easiest, cheapest way for us to stabilise our climate is to stop cutting forests down and keep them standing”.
Here, we explore the two viscose alternatives that are ready to to be scaled up to commercial capacity.
Viscose made from recycled cotton
According to Rycroft, clothing waste is the most exciting alternative feedstock because it is so abundant. “There are 100bn items of apparel produced every year and 60% of it is in landfill within 12 months,” she says.
But turning old clothes into viscose is not without its challenges. Collecting textile waste is difficult – aside from charity bins and drop-off points, there is limited infrastructure to do so and garments need to be manually or mechanically sorted by fibre type.
To be recycled into viscose, garments need to be made of plant-based fibres like cotton, linen or hemp. Right now, the available technology is focused on processing 100% cotton, as it is by far the most common natural fibre.
Globally, there are a few companies with textile recycling technologies, including Evrnu, Södra and Lenzing, but Rycroft describes Renewcell – a Sweden-based textile recycling company – as the most exciting. It has launched its first pulp mill for next-generation viscose production, which will be able to produce 120,000 tonnes of material by early 2024, making its commercial capacity much greater than its competitors.
At Renewcell, 100% cotton garments are shredded, then chemicals are used to turn the fragments into a slurry that is bleached and dried to produce sheets of cellulose that look and feel like thick white cardboard. These sheets are then sent off to be turned into a viscose substance that is extracted into yarn.
The resulting material is called Circulose. Rycroft says compared with traditional viscose, the process emits “5 tonnes less carbon per tonne of product than a conventional wood product and uses 90% less water and fewer chemicals”.
Circulose has already made some public appearances in the market. In 2022, Levi’s released a range of 501s made with a Circulose blend; and earlier this year, Canadian pop singer Shawn Mendes’ capsule for Tommy Hilfiger featured a rugby shirt made with Circulose fibres.
At the Future Fabrics expo, the Circulose material on display felt like a thick cotton jersey with a bit of stretch, but without the softness, lustre or elasticity of modal or lyocell, or the warmth and weightlessness of pure cotton.
The material was made of one part recycled cotton and two parts virgin wood pulp, but this reliance on virgin materials will decrease as the factory’s capacity for scale and the technology to use it in the supply chain improves.
Viscose made from coconut water
In the context of viscose production, food waste refers to the byproducts of large-scale, industrial food processing like fruit peel, or the remnants of brewing beer.
Nullarbor fibre, by Australian company Nanollose, is a next-generation viscose derived from coconut water, a byproduct of coconut processing.
The Nanollose executive chairman, Wayne Best, says the company could, “in theory … use a whole pile of different types of food waste” to produce the cellulose for viscose rayon, as long as the waste contains a sugar.
To create the cellulose, bacteria are added to the coconut water, which kickstarts a fermentation process similar to making yoghurt. “The bacteria converts the sugars into cellulose and in doing so, it generates its own heat,” Best says.
The cellulose is turned into a viscous substance that is pushed through spinnerets to make a translucent yarn, which is the staple fibre used in lyocell.
According to Valerie Langer, a strategist at Canopy, since the process requires very little land, water or energy and the production cycle is just 18 days, the potential for scale is enormous. This is distinct from other food waste feedstocks like orange peel, which has limitations at scale – the peel needs to be refrigerated to prevent it from going mouldy.
“You can actually get more fibre per hectare growing microbial cellulose than growing trees, because it grows in weeks rather than years,” she says.
While Best says a “small number of garments” made using coconut waste will be available by the end of the year, in late 2022 Nanollose proved its concept by creating its first wearable item – a jumper. The material on display at the London expo is soft, thin and very stretchy. It has a similar feel to a lightweight lyocell or bamboo that might be good to wear close to the skin as you would with underwear or workout gear. But it’s missing the drape and density that would make it suitable for other garments such blouses or trousers.
Since the process can be applied to other forms of food waste, Nanollose is looking to Indonesia to manufacture commercial quantities of Nullarbor fibre and develop a supply chain and ecosystem around food waste.
