Until recently, recycling cotton was not possible for technical reasons. A team of researchers at Fraunhofer IAP was the first to produce a viscose filament yarn made of recycled cotton.
Cotton clothing is usually incinerated, converted into cleaning rags or ends up in the landfill. “One day soon it will be possible to recycle it over and over again – to produce new garments from used shirts, pants and dresses,” says Dr. André Lehmann, researcher at the Fraunhofer Institute for Applied Polymer Research IAP in Potsdam. Working on behalf of the Swedish company re:newcell, the chemist and his team succeeded in converting the pulp from recycled cotton into viscose rayon fibers made of pure cellulose – one step closer to greater sustainability in the fashion industry.
Although Germany does recycle old clothes, they end up as inferior products such as cleaning cloths rather than new garments. This is because pants, shirts and other articles of clothing are rarely made from a single type of fabric. There has never been a way to separate the intertwined fibers of these blends.
The textile industry usually uses pulp as the starter material for producing regenerated cellulosic fibers such as viscose rayon, modal and lyocell. The feedstock for this pulp is usually wood. “However, re:newcell sent us cellulose sheets made of recycled cotton and asked us to find out if they could be converted into viscose rayon fibers. “We were able to extract the foreign fibers from the pulp by setting the right parameters for both the dissolving and spinning processes, for example, with effective filtration stages,” says the researcher. This yielded a filament yarn – that is, a continuous strand of fiber several kilometers long consisting of 100 percent cellulose, the quality of which is comparable to that of wood-based regenerated cellulosic fiber. Compatible with the standard industrial process for making viscose rayon, the new fibers spun from this cotton pulp are suitable for mass manufacturing.