Mechanical and Chemical Textile Recycling
Sorting of wool garments before mechanical recycling process at Manteco
Globally we are drowning in second-hand textiles, without the correct infrastructure to deal with this overconsumption textile waste either gets dumped in landfill, shipped to other countries ( that’s a whole other blog post), or incinerated. Currently, 87% of the material used for clothing production is landfilled or incinerated after its final use (Ellen MacArthur Foundation, A new textiles economy: Redesigning fashion’s future (2017).
Without a doubt, we need to improve and scale recycling and sorting facilities as well as create more demand for recycled fibres. But what are the current methods of recycling that are available? And what are their benefits and limitation?
Mechanical Recycling
Mechanical recycling is the process of taking unwanted textile fabric and without the use of any chemicals and processing it into new yarn. The process starts by sorting garments into material type and colour and removing anything that isn’t wool, such as zips, buttons and even stitching. Next, the fabric is shredded into smaller pieces. Finally, the fabric is passed through a carding machine, which uses metal pins to break the fibers and align them to be parallel to one another creating a homogenous fibre which can be spun into yarn.
Pros
The process doesn’t require the new yarn to be dyed and therefore doesn’t require water. Instead, new colours can be created by skilfully mixing different batches of recycled yarn.
Cons
Because materials are shredded in order to recapture the fibre this often results in inferior quality fibres compared to virgin fibres. Consequently for the resulting fibre to be of use it is necessary to add stronger and longer virgin fibres.
Fibre-recycling processes cannot separate blends of fabrics or filter out dyes and contaminants.
Manteco is an Italian company that has been mechanically recycling wool since 1943. Have a look at their website for a great explanation of their recycling processes.
Chemical Polymer Recycling
Chemical recycling takes fibres back to a polymer level or back to their basic building blocks. This process works by dissolving the fibres in chemicals, after all buttons, zips and other fixing have been removed. Different chemicals and extrusion processes are then used to reform the liquid into new fibres. This process can be utilised for both cellulose and plastic-based fibres.
Pros
The recycling fibre is often of the same quality as its virgin counterpart.
With the right research and investment, there is a lot of potential for significant improvements in chemical recycling, offering a potential solution
Cons
If not properly managed, the chemicals used in these processes can be harmful to people and the environment. The best companies working in this area used non-toxic chemicals as well as creating closed-loop systems so nothing harmful can escape into the environment.
More infrastructure and innovation is needed to offer scalable solutions.
Take a look at Tencel’s REFIBRA™ technology for an example of the chemical recycling of cellulose.