A Better Guide To Viscose and Rayon

 

Viscose is loved by clothing brands for its affordability, easy dyeing, and the beautiful way it drapes. A cheap alternative to silk that also blends well with other fabrics, it is no surprise that viscose is the third most popular textile in the world, trailing only cotton and polyester.

Viscose is also derived from plants, so many manufacturers claim it is a sustainable option. But serious questions have been raised in recent years over the true eco-credentials of viscose. Let’s look in more detail at this popular fabric and whether it can really claim to be an eco-friendly textile.

What is Viscose?

Viscose is a textile made from cellulose (plant fibres). Unlike cotton, hemp, or linen, which are made from plant fibres that are naturally soft, viscose fabric is formed from cellulose from trees and woodier plants such as bamboo or sugar cane.

Fabric made from wood pulp was first invented in the late 19th century, by French scientist, Hilaire de Chardonnet, who was trying to come up with an affordable alternative to silk. But the original fabric was so flammable that it wasn’t commercially viable, bursting into flames rarely being the fashion statement people are after.

A few years later, British scientists Charles Frederick Cross, Edward John Bevan, and Clayton Beadle patented a safer version and named it viscose. It has been used commercially since the early 20th century.

Viscose is popular with the fashion industry and is found in a wide range of clothing. Because it blends well with other fabrics, you’ll often see viscose used alongside cotton, linen, or wool, as well as on its own in 100% viscose dresses, skirts, and tops.

You’ll also find it used in carpets, bedding, and upholstery fabrics. It’s even used to make casings for sausages!

Wait, what is rayon then? Are they the same thing?

Because of its qualities, modal fabric is used in activewear, underwear, pyjamas and bed sheets. Take a look at your clothing and you will be surprised to see quite a few items will probably be made out of modal, or some sort of modal blend. Most high quality gym wear is made from it as it is the best material out there for activewear. It is strong and flexible, and also extremely water absorbent, over 50% more absorbent than cotton, perfect for times when you are getting all sweaty in the gym!

It is more expensive than other types of fabrics such as cotton or synthetic materials, so it is mostly used by more high-end companies that value quality over price.

Is viscose/rayon a natural fabric?

Generally, fabrics are split into two different categories. Natural fabrics, like cotton, linen, or hemp, are derived from plants. Others, including wool, leather, and silk, come from animal sources. Artificial fibres, such as polyester, acrylic, or nylon, are manufactured from different chemicals and are considered to be man-made.

Since viscose textiles are made from plant fibres, you might assume that they would be classed as natural. However, fabrics made from wood pulp go through an intensive manufacturing process to turn the tough cellulose into a soft fabric suitable for clothing.

Because of the amount of human intervention and chemicals needed to produce viscose and other forms of rayon, these fabrics fall into an in-between category and are usually classed as semi-synthetic textiles.

How is viscose made?

It takes a lot of processing to get from a eucalyptus tree or a stick of bamboo to a t-shirt. First, wood chips need to be turned into wood pulp, using sodium hydroxide (caustic soda) to break down the wood.

Once dissolved, the wood pulp solution is pressed between rollers to form sheets, which are then crumbled up and treated with carbon disulfide.

The treated pulp is dissolved in sulfuric acid, forming the thick, viscous liquid that gives viscose its name. This is then formed into fibres by a machine called a spinneret.

Finally, the fibres are spun into yarn to make viscose fabric and it’s ready to be made into clothing.

So, is viscose an eco-friendly material?

When it comes to sustainability, viscose fabric does have some good points. Since it is made from plants, it is biodegradable, unlike synthetic materials like acrylic and polyester. It requires significantly less water than cotton. And being made from trees and plants mean that it is from a renewable source, technically at least.

But there are some major issues with viscose that have been garnering attention over the last few years, with high-profile campaigns from organisations like Canopy, the Changing Markets Foundation, and Fashion for Good challenging viscose’s status as a sustainable material.

The problems fall into two main areas; the source of the raw materials, and the processes used to turn them into fabric.

Raw materials

From an environmental perspective, a major issue with viscose is where the raw materials that make the fabric come from. Although well-managed, fast growing plantations could be argued to be a sustainable source of wood pulp, the harvesting of trees from natural forests to make viscose has been linked to deforestation, with the associated loss of habitats and biodiversity.

Canopy estimate that almost half of all the wood pulp used to produce viscose worldwide is sourced from ancient and endangered forests, including the peatlands of Indonesia and the ancient boreal forests of Canada. Far from being a sustainable source, the loss of these valuable carbon sinks is seriously bad news for the planet.

Natural forests are integral in managing climate change. Per hectare, they can store up to 40 times more carbon than commercial plantations, so their loss has a devastating impact on efforts to manage the release of carbon into the atmosphere.

It’s not just carbon segregation that matters either. Natural forests are complex habitats which provide critical protection to thousands of species. Their loss endangers biodiversity – according to the World Wide Fund for Nature (WWF), over half of the land-based animals and plants in the world live in or around forests.

Canopy estimate that 150 million trees are cut down each year to make viscose.  What is even more tragic is the amount of wood needed; it takes 3 tonnes of wood to make just 1 tonne of rayon and 70% of the tree goes to waste. Canopy say that 3.3 million tonnes of this wood still comes from ancient and endangered forests.

What about bamboo viscose?

Bamboo has long been hailed as an eco-friendly alternative to using slow-growing trees for textiles, furniture, and other household items. It grows extremely fast, meaning it can be harvested and replenished within a short timescale. It can also be grown on land that isn’t suitable for other crops. Many clothing brands that market themselves as being eco-friendly use bamboo viscose in their clothes and underwear.

As so often when it comes to sustainability, the eco-credentials of bamboo aren’t clear-cut. When harvested from well-managed sources, bamboo can be a good alternative to other raw materials for viscose. But the demand for bamboo-based products is driving deforestation, with natural forests cleared to make space for bamboo plantations.

Bamboo is also processed in the same way as other woody fibres to make viscose, so the same issues with pollution and health can arise (more on this below).

In short, whether bamboo viscose is an eco-friendly alternative to other viscose fabrics will depend where it is sourced and how it is manufactured. Canopy advise that bamboo should be FSC certified, should not be harvested from ancient or endangered forests, should not be cultivated where it will displace food crops or put unreasonable strain on regional water supplies, and should be processed in closed-loop facilities to reduce waste and pollution.

Check the details with your favourite bamboo clothing brand before making a decision about whether to go ahead with purchasing your next pair of bamboo leggings or t-shirt. If they are truly eco-friendly, they should be paying attention to where the raw bamboo that makes their clothing comes from.

Manufacturing processes

We’ve already looked briefly at the intensive processing that goes into turning wood pulp into viscose fabric. It is no surprise that the use of all of those chemicals comes at a cost, both to people and the environment.

What are the health impacts?

In traditional viscose manufacture, carbon disulfide is used to treat the wood pulp before it is spun into fabric. But this chemical has serious consequences for the workers who make viscose. Studies have found that carbon disulfide is associated with a range of health issues, including heart disease, cancer, birth defects, and psychiatric disorders.

The effects of carbon disulfide aren’t limited to those working directly with it either. A 2017 investigation by the Changing Markets Foundation into viscose manufacture in China, Indonesia, and India found that emissions from processing facilities can spread carbon disulfide into the surrounding area, causing health issues for local communities.

From the point of view of the consumer, the good news is that there’s no reason to worry about health issues from wearing viscose clothes. Viscose fabric is thoroughly washed before it is made into clothes, so by the time it reaches the shops, it is safe to wear. But the effect on the people earlier in the supply chain is extremely concerning.

As well as exposing workers and communities to the health risks of carbon disulfide, the processing of wood pulp into viscose materials uses a lot of caustic soda (sodium hydroxide) which can cause burns and is toxic when inhaled.

Additionally, a toxic gas called hydrogen sulphide is released as a biproduct of the spinning process. Hydrogen sulphide can cause eye irritation and neurological changes. It also has a distinctive smell of rotten eggs, which is a frequent complaint from communities living near viscose processing facilities.

What about the environmental impact?

Turning wood chips into yarn requires a lot of water, which is then mixed with polluting chemicals. If care isn’t taken to properly clean the water before it is released back into nearby rivers and lakes, the impact on local waterways can be severe.

In their 2017 investigation, the Changing Markets Foundation visited ten major manufacturing sites in India, China, and Indonesia to assess the impact of viscose production on the local environment. At the majority of sites, they found that water in local lakes and rivers was polluted with wastewater from viscose-processing facilities.

At Poyang Lake in China, for example, the investigators tested wastewater from one of the two viscose factories that discharge water into the lake. They found that it was acidic and contained ten times the permitted levels of zinc.

This water pollution isn’t just toxic to aquatic wildlife. Locals report the knock-on effect of water pollution on fishing stock, which prevents them from making an income from fishing. The contaminated water also pollutes water that was previously used by local communities for drinking.

Is it all bad news?

Deforestation, hazardous chemicals, and pollution – it isn’t looking like a positive picture so far. But wait; before you swear off all rayon fabric for life, there is some hopeful news. Fashion brands and manufacturers are well-aware of the issues with viscose and some of them have sworn to make changes.

Going ‘rainforest-free’

In 2017, Canopy and the Rainforest Alliance launched their initiative to make viscose ‘rainforest-free’, giving clothing brands a way to assess their risk of sourcing viscose from ancient or endangered forests.

Producers can sign up to a CanopyStyle Audit, which assesses their supply-chain to ensure that the raw materials used to make their viscose is sustainable. By 2020, 12 of the 42 viscose manufacturers worldwide had signed up to the audit process, and many others are moving towards it, giving fashion brands more confidence in how the viscose used in their clothing is made.

According to the 2020 Full Circle report from Fashion for Good, viscose producers that use sustainable forestry practices can have a net positive environmental impact, by planting more trees than they harvest. But as we’ve seen, raw materials aren’t the only issue in the manufacture of viscose.

Tackling pollution

Water and air pollution from wood pulp processing can cause real damage to the environment, as we’ve discussed. However, by managing their chemical use carefully in a closed-loop system, viscose producers can reduce, and even eliminate, their polluting environmental impact.

A closed-loop system is one that reclaims and reuses the chemicals used in the manufacture of viscose via water treatment processes and measures to prevent emissions into the air. The technology to do this is already available – producers just need to be willing to make the investment in upgrading their facilities.

The Changing Markets Foundation have developed a roadmap that viscose producers can use to move their factories onto a closed-loop system that doesn’t damage people or the environment. The Foundation are encouraging fashion brands to put pressure on their suppliers to clean up their act.

You can check how popular brands are doing on the transition to responsibly produced viscose by checking the Changing Markets Foundations’s Brand Categorisation table.

What about those harmful chemicals?

This is where it is important to understand the difference between the various forms of rayon because those subtle differences in the manufacturing process can have a big effect on their environmental and health impacts.

Viscose is made with a process that includes the use of carbon disulfide, the harmful chemical we looked at earlier that causes all sorts of health issues for those working with it. But producers are coming up with different manufacturing processes to address the use of this chemical, leading to some alternatives to viscose. Let’s take a look at a couple of them:

Modal

Modal is produced from cellulose from beech trees. Originally manufactured in Japan, modal is made in a very similar way to viscose, but results in a stronger, more water absorbent fabric, which is often used for underwear, sportswear, and bedding. The manufacturing process differs slightly too – importantly, modal uses less chemicals than viscose.

So far, so good. But modal does still use carbon disulfide in the manufacturing process. It may be less harmful than traditional viscose, but it still has the same issues with the supply of raw materials and the need for a closed-loop system to prevent pollution, so fashion brands need to be careful of where they source their modal.

Lyocell

Lyocell is often marketed under the brand name Tencel, which belongs to European manufacturer Lenzing. The first viscose producer to sign up to CanopyStyle’s audit, Lenzing appear to be taking the call to produce a truly eco-fabric from cellulose seriously, and their Tencel lyocell is part of that.

Like viscose and modal, lyocell is made by processing cellulose. The difference is that it doesn’t use sodium hydroxide and carbon disulfide, switching them for the less toxic organic compound N-methyl-morpholine-N-oxide. This difference in the manufacturing process gives lyocell slightly different properties to viscose, but it still drapes and dyes well.

Of course, the sourcing of raw materials and the potential for pollution are still present with lyocell, but Lenzing say that more than 99% of the wood used to manufacture their Tencel is certified ‘according to recognised sustainability criteria’ such as that used by the Forest Stewardship Council.

Lyocell/Tencel is growing in popularity, although it still holds only a small share of the overall rayon market at 4.2%. In 2019, viscose manufacturers Birla Cellulose and Sateri both announced their intention to increase their lyocell production.

That means all three of the biggest rayon producers in the world are paying close attention to the growth of lyocell as a fabric of choice for fashion brands. We can likely expect to see many more clothing lines using Tencel instead of traditional viscose in the near future.

Where next for rayon?

Positive changes have been occurring over the past few years, with fashion brands and manufacturers both getting to grips with the issues behind traditional viscose. But campaigners are ready to take things a step further.

Canopy and Fashion for Good have both released new reports in 2020 announcing their intention to focus on the use of recycled cotton and viscose to make new viscose fabric.

Not only would this protect ancient and endangered forests, by moving the supply chain from virgin materials to recycled textiles, but it would also address the huge issue of waste in the fashion industry.

20 million tonnes of cotton fabric are wasted every year. According to Fashion for Good, turning just 25% of this waste into new viscose fabric would eliminate the need to use virgin wood fibre at all. That’s a pretty powerful outcome if manufacturers can pull it off.

The idea is new as yet, but viscose producers are already seeing the potential. From Lenzing’s  Refibra to Tangshan Sanyou’s ReVisco, manufacturers are beginning to experiment with producing viscose from waste cotton.

The percentages are currently low – 30% of Refibra and 50% of ReVisco are made from wate fabric, while other producers’ offerings are still at below 20%. But with recycled raw materials, closed-loop systems, and the reduction of toxic chemicals, viscose may yet be able to claim status as a truly eco-friendly material.

What can we do to help?

As a consumer, being aware of the issues and holding our favourite brands accountable is a great way to support a change to more sustainable viscose production. If we put pressure on fashion brands, they in turn will put pressure on their suppliers, leading to better practice all round. Simple actions you can take include:

  • Check the label. Knowing what your clothes are made from is the first step in making buying decisions that support your values.
  • Look out for brands that are working towards using responsible viscose sourcing and reward them with your custom. Use Canopy’s ‘Hot button’ reports and the Changing Market Foundation’s Brand Categorisation guide, as well as information from individual brands on how they source viscose and rayon fabric.
  • If a brand you love isn’t doing well, write to them. Explain your concerns and ask them what they are doing to make sure their viscose is responsibly sourced. The more of us who show we care, the more likely brands are to pay attention.

Traditional viscose fabric falls down on a number of eco-credentials. But the potential to do better is still there.

Together, we can hold brands accountable and make sure that the future looks green for this plant-based fabric.