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Green Chemistry

Organizations pursue greener textiles

Celanese unveils recyclable elastic fiber, BASF and Aarhus University develop processes for separating nylon from mixed textiles

by Alex Scott
January 24, 2024 | A version of this story appeared in Volume 102, Issue 3


A jacket made from recycled nylon 6.
Credit: BASF
A jacket made from recycled nylon 6

Several companies and a university are claiming advances in recycling textile fibers, efforts they hope will make a dent in the millions of metric tons (t) of textile waste that are landfilled or incinerated every year.

Celanese and the apparel maker Under Armour have introduced Neolast, an elastic fiber made from an elasto-ester polymer that they claim is readily recyclable. The commonly used stretch fiber elastane, also known as spandex or Lycra, is not easily recyclable.

The firms say their melt extrusion process for making Neolast is solvent-free and eliminates the use of hazardous substances typically used to create spandex. Celanese and Under Armour say they are working on systems for recycling Neolast.

Additionally, the process for making Neolast is more precise than the one for elastane, as yarn spinners can “dial power-stretch levels up or down and engineer fibers to meet a broader array of fabric specifications,” Celanese says in a press release.

Elastane was invented by the DuPont chemist Joseph Shivers in 1958. A non-biodegradable polyether-polyurea copolymer, it is typically mixed with fibers such as cotton to make garments.

In a separate initiative, BASF and the clothing retailer Inditex say they have developed the first circular process for making nylon 6 yarns entirely from textile waste. The process involves shredding garments and then depolymerizing nylon 6 into the monomer caprolactam. Following a purification step, the caprolactam is repolymerized into nylon 6. The partners call the new material Loopamid.

The industry still needs to boost new collecting and recycling capacities in order to close the loop and scale recycling for post-consumer waste.
Javier Losada, chief sustainability officer, Inditex

The Inditex subsidiary Zara has made a jacket—including the fabric, buttons, filler, and zipper—entirely from Loopamid. BASF and Inditex worked with the zipper maker YKK and the fastener company Velcro, among others, on the technology.

Loopamid is “a first step to move towards a circular solution, as the industry still needs to boost new collecting and recycling capacities in order to close the loop and scale recycling for post-consumer waste,” Javier Losada, Inditex’s chief sustainability officer, says in a press release. BASF and Inditex cite the Ellen MacArthur Foundation’s estimate that 92 million t of textile waste are dumped or incinerated every year.

Separately, researchers at Aarhus University have developed a lab-scale process for separating nylon from elastane. The links in the elastane polymer chain are bound together by diamine groups. By heating the clothes to 225 °C and adding tert-amyl alcohol, the researchers were able to break down the diamine bonds.

“When this happens, the chains fall apart and the materials separate,” Steffan K. Kristensen, an assistant professor at Aarhus, says in a press release. The project was detailed in a recent edition of Green Chemistry.



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