Published 2018-01-04

This post is also available in Swedish

Recycling with global potential

Blend Re:wind, a process developed in Mistra Future Fashion, means that it is now both economically viable and practicable to recycle textile materials composed of both cotton and polyester. The method is deemed to have great potential on the global market.

Recycling textile materials comprising both cotton and polyester is troublesome. Now Mistra Future Fashion is launching the Blend Re:wind process, which means that it will soon be both economically worthwhile and practicable to recycle textile materials made of a blend of cotton and polyester.

Ever since Mistra Future Fashion started six years ago, better textile recycling systems have been a primary objective. To succeed, both methods of sorting end-of-life textiles, and processes of recycling various types of fibres are needed.

Today, there are several systems and solutions on the market. The disadvantage of most of these is that they are resource-intensive while causing heavy wear on the fibres to be reused.

‘When Mistra Future Fashion started, we began working with cotton. But after a few years we chose to switch to more complex materials, not least because we saw that textiles containing cotton and polyester are becoming more common,’ says Hanna de la Motte, who is responsible for developing recycling solutions in Mistra Future Fashion.

Why the combination of cotton and polyester has become so interesting is because the material is getting more robust, which is good in terms of sustainability and resources. At the same time, the polyester helps to speed up the drying of textiles after washing, which reduces energy use.

The process of separating cotton from polyester that the researchers in Mistra Future Fashion have developed has been named Blend Re:wind. Using simple basic chemicals, it is now possible to remove the cotton component in the form of a high-quality viscose filament. The polyester contained in the material comes out in two separate streams, which can then be easily reconstituted as a new, adequate raw material.

‘We’ve worked hard to improve the quality of the regenerated fibre, and we believe we’ve managed well. The fact that the cotton going into the process can’t become new cotton isn’t a problem or anything we’d expected to succeed with. The fibres we extract can, instead, be used to produce viscose and lyocell. And those aren’t bad alternatives at all, not least because we have industrial means of manufacturing these materials in Sweden.’

The technology exists. So far it only works on a laboratory scale, but intensive work is being done to upscale the method.

‘Going from lab to a large scale is costly, so that’s the biggest challenge right now. One advantage of our method is that it enables the process to be integrated into existing industry, which improves the prospects of it being put to practical use.’

One question yet to be answered is how many times a textile material can be recycled before the fibre quality becomes too poor.

‘The strength of Mistra Future Fashion is that we look at the entire value chain and have all the key operators in the field in our consortium. It means that we can work in parallel with methods for recycling textile fibres and systems for sorting different materials more efficiently,’ de la Motte says.

The idea is that, in the long term, to commercialise Blend Re:wind; and the assessment is that the method has the potential to succeed in the global market. But initially, it is textile materials recovered from the service sector that will be recycled. The advantage of starting there is the input material is easily controllable.

When systems for sorting mixed textiles become more efficient, it will be possible to recycle the eight kilos of textiles that the average Swede bins each year.

Facts about textiles

Swedes buy an average of 50 garments a year. Whether that is a lot or not is hard to say; our individual needs are, after all, very different. What we know, however, is that the clothes we carry home from the shops have affected the environment in one way or another. For fashion to become more sustainable, the entire chain needs to be changed, so that consumers wear the garments longer and recycle as much as possible.

Some of the most common textiles are listed below.

Cotton is one of the most common and also one of the worst materials in environmental terms, not least because it is a water-consuming crop that is often grown in dry areas. In addition, a quarter of the world’s pesticides are used for cotton cultivation. Recycled cotton cannot become cotton again. However, it is possible to make viscose out of worn cotton fibres.

Polyester, unlike cotton, has no direct impact on the land surface and requires no pesticides. Polyester also requires fewer chemicals when it is dyed. The downside is that it is made of crude oil — a resource both finite and environmentally harmful. But polyester can also be produced from recycled plastic. Thus, the material can both benefit and harm the environment.

Blend materials of cotton and polyester have become increasingly common, not least because the mixing makes textiles stronger and speeds up their drying after washing — desirable characteristics, since they help to extend the life of textiles while reducing energy use.

Viscose, which is made of cellulose, is an excellent and useful material. It has had a somewhat tarnished reputation because converting cellulose into a textile fibre has required large amounts of chemicals. New and more environment-friendly methods have boosted interest in viscose. One good way of making it, for example, is to use recycled cotton.

Lyocell is a cellulose-based textile material with a marked silken feel. Just like viscose, it can be produced from recycled cotton fibres. The advantage of lyocell is that its fibres can be which in turn makes the material durable. Like viscose, lyocell is now manufactured in closed systems, which makes the process environment-friendly.

Per Westergård