Viscose (lyocell process)

Where does viscose come from?

Viscose is an artificial chemical material, made from regenerated cellulose from plants such as cotton or bamboo. This chemical process for transforming natural fibres was invented by a Frenchman: Hilaire de Chardonnet. In 1884, he tried to imitate silk by replacing silkworms with plant cellulose taken from wood pulp.

Today viscose is widespread in the textile industry and a staple of clothing. An estimated 99 million tonnes of wood pulp are used every year worldwide to produce viscose! You'll find it in t-shirts as much as in trousers, dresses or skirts… It's a very versatile material !

Why replace natural fibres with artificial fibres?

Some natural fibres produce a fabric that is rather rough, thick and unpleasant to the touch. Viscose transforms plant cellulose to recreate artificial fibres that are much softer, finer and smoother. The fabric made from this material, viscose (also called artificial silk or rayon), is very fluid, glossy, soft, fine and comfortable to wear for sensitive skin. It gives a very clingy, flowing look to dresses or t-shirts, for example. Viscose fabrics are very hard-wearing and they also hold colour well. They stand up to repeated washing better than natural fibres, which can fade. For those of us in a hurry, this very fluid fabric hardly creases and rarely needs ironing!

But viscose also has a few drawbacks compared with natural fibres. Artificial viscose fibres don't absorb moisture and don't retain heat. So they aren't suited to winter clothing or technical sportswear, and can be uncomfortable when you sweat.

Pay close attention to the manufacturing process: choose the Lyocell process.

The "conventional" manufacturing process for viscose is polluting and uses a lot of natural resources. Viscose is obtained through a chemical process that recreates artificial fibres from plant cellulose. All sorts of plant fibres can be used to make this artificial silk, from cotton and bamboo to eucalyptus. First, a mixture of sodium sulphate and citric acid is used to extract the plant cellulose from the natural fibres. Carbon disulphide is then used to turn this mixture into a plant pulp, which is then drawn into yarns and woven. The yarns are then cooled using sulphates that set the fibres.

This chemical process therefore has a significant negative environmental impact:

1. First, citric acid and sodium sulphate are toxic chemicals that are often not recycled. In the developing countries where viscose is made, where there is no treatment of chemical waste, they are released into nature and rivers and pollute ecosystems.
2. Carbon disulphide is a toxic, flammable and highly volatile substance. It causes serious air pollution.

The manufacturing process for artificial fibres also uses a great deal of water and wastes a large share of the natural plants. It takes around 1kg of natural fibres to obtain 400g of regenerated viscose fibres, which contributes to deforestation. In terms of health and social impact, workers in these factories face a chemical environment every day, which can prove toxic and seriously affect their health if they aren't properly equipped. Finally, the chemicals used in the manufacturing process end up in the viscose fibres and in the finished product, in constant contact with the consumer's skin.

The Lyocell process, on the other hand, is more environmentally friendly.

This process uses a non-toxic, recyclable organic solvent: NMMP (N-methylmorpholine N-oxide monohydrate).

Dissolving wood cellulose in this solvent produces a viscous mixture. The cellulose appears in the form of fibres. These are washed and dried before being wound together. They then produce finished fibres made from organic bamboo, eucalyptus or hardwood material. Once the manufacturing process is complete, 99.7% of the solvent used to dissolve the fibre is recovered in a rinsing tank.

This almost complete recovery of the solvent is therefore a major economic and environmental advantage.

Once recovered and dried, the fibres are used to make a wide range of clothes.

Is viscose (Lyocell process) environmentally friendly ?

Risks of intensive monocultures

Even though we don't have exact figures on the subject, we need to stay vigilant about the wood pulp used to make viscose (even with the Lyocell process). While the wood is supposed to come from certified, sustainable forestry operations planted specifically for its production, this should be checked. Tencel is an artificial fibre made from a plant-based raw material which, if poorly managed, can harm the environment. Plantations made up of a single tree species (monoculture) don't support the same biodiversity and can prove harmful to the environment : these single-species forests are more vulnerable to storms and fires and are less resistant to disease. Growing a single species, which always draws the same nutrients, depletes the soil. So it's important to find out about the traceability of this naturally sourced cellulose.