From cotton waste to viscose

With a production of 26 million tons, cotton is the most widely used natural fiber in fashion and, consequently, the natural fiber offering the greatest quantities of waste and scrap. 

 

Reliable estimates reveal that more than 40% of the fibers are lost in the supply chain. Post-industrial waste is produced in the initial stages, during spinning, selvedges are cut out during weaving, defective fabrics are scrapped and there is also waste resulting from the cutting process in garment making, the growing problem of pre-consumer waste: items that remain unsold even after sales management in dedicated channels. Only a small portion of post-consumption textile waste, including end-of-life items, is recycled. 

 

The lower unit value of cotton and the shorter length of its fiber has historically made the recycling of cotton more difficult and less important compared to that of the so-called "noble" fibers, like wool. Cotton waste and scraps are generally destined to down-cycling, i.e. value loss. They are used in the fields as fertilizer or they are sent to incinerators in the best case scenario or dumped in landfills, in the worst.

 

Cotton has a very high cellulose component, e.g. linters, the cotton fibers scrapped during the ginning phase, are traditionally used in the production of refined paper. Today, the recent evolution of technology allows to use cotton waste also in the production chain of viscose, the oldest man-made fiber. Challenged by the environmentalists (see the Dirty Fashion report by the Changing Markets Foundation published in 2018) due to its high environmental impact and the toxicity of the chemicals involved in its manufacturing, viscose is experiencing a rebirth, and is ready to become part of the circular economy model for the textile industry, as urged by the European Union and the 2030 Agenda. 

 

The first step was the introduction of closed-loop technologies pioneered by Lenzing with Tencel™. The second breakthrough was the development of technologies to extract the cellulose portion from recycled cotton, with global companies involved, including Lenzing with Refibra and Aditya Birla, as well as new startups such as the Swedish Re:newcell with the Circulose brand, and spin-offs from university research centers, such as the Finnish company Infinited fibres. 

 

Today, research focuses on the next fundamental step, i.e. the separation of the cotton portion from polymeric fibers such as polyester, with which cotton is frequently used in mixed compositions. 

Cotton recycling has a new future. The increasing consumption of fibers calls for a reduction in waste and the development of synergies between spinning mills, weaving companies, fashion brands and the new generation of viscose producers is an interesting scenario that needs, however, to be organized to more effectively collect, store and recycle fiber waste. This strategy has the potential to give cotton a leading role in the circular economy.

 

• Sustainable technologies