The typical individual in Europe produces around 15 kg of textile waste annually, mostly from worn clothes and household textiles. This leads to issues with disposal, both inside and outside of Europe, whether by landfilling or incineration.
Simultaneously, the textile sector has difficulties with recycling: today, less than 1% of clothing produced globally is recycled back into clothing (a process known as fiber-to-fiber recycling), while over 14% is turned into other products.
According to a McKinsey report from 2022, Europe now has a clothing collection rate of 30–35%. A large portion of the unsorted garbage is transferred outside of Europe, mostly to Africa. Furthermore, the majority of fiber-to-fiber recycling processes have stringent input criteria; some of them only accept clothing made of monofibers.
The Difficulty of Combination Textiles
As per the Waste Framework Directive of the European Union, worn textiles need to be collected and recycled throughout the EU starting on January 1, 2025. Mixed fabrics may be difficult to recycle, however, particularly if they include elastane, often known as spandex.
Many of the yarns and textiles used to produce apparel, including pure cotton, polyester, or polyamide, are readily recyclable when they are in their 100% form. However, when elastane is added to materials—even in little amounts—conventional recycling techniques become challenging, if not impossible.
Emanuel Boschmeier, a researcher at the Vienna University of Technology (TU Wien), Austria, claims that because elastane is so elastic—as the name implies—it cannot be handled by shredders used to shred textiles prior to recycling, causing clumping, blockages, and soiling in the machinery.
Elevated Content of Elastane
The main problem is clothing with more than 10% elastane content. Jean Hegedus, director of sustainability at the Lycra Company, USA, made this claim while speaking at the Dornbirn Global Fiber Congress in September. He said that while some clothing with an elastane content of 2-5% can be mechanically recycled, clothing with an elastane content of 5–10% is typically recycled into items like building insulation and the interiors of automotive seating.
The recycling of clothing with elastane presents a number of obstacles:
Fiber identification is challenging because precise, automated fiber sorting and pre-processing are not yet widely accessible. Elastane-containing fabrics may sometimes block filters, necessitating system clean-outs and shutdowns; elastane can occasionally have an impact on companion fiber viability, depending on the particular recycling technique and chemicals being used for purification.
Scaling the circular economy for textiles would need scalable systems that can lower costs and boost production, as well as updated scanning and sorting technologies, recycling systems that can handle fiber mixes that contain elastane. McKinsey projects that, notwithstanding these obstacles, fiber-to-fiber recycling might account for 18–26% of global total textile waste by 2030.
The Lycra Company is working with a few select recyclers on several technologies for recycling different Lycra fiber blends, such as with cotton, polyester, and polyamide, in order to address the issue of elastane recycling. They are also developing a Lycra fiber that can be easily extracted from clothing, collected, and re-spun into new garments.
EcoMade Lycra T400 Fiber
At Dornbirn, Lycra T400—a stretch fabric but not an elastane—was also shown. It is an elasterell-p bicomponent yarn that gives textiles elastane-free stretch. It is an elastomultiester polyester made of polyethylene terephthalate and polytrimethylene terephthalate. About 15–18% of the fiber in Lycra T400 EcoMade comes from plant-based sources like maize.
The Lycra Company began testing mixes with polyester using a recycler that uses glycolysis, a well-known chemical recycling technique. The results demonstrated that Lycra T400 did not interfere with regular polyester recycling streams.
Additionally, it was discovered that the recycled fiber’s fabric performance was acceptable and that it could attain aesthetics similar to a control fabric with a few minor tweaks made during the chip manufacture process.
Another experiment looks at breaking down colorful textiles made of Lycra T400 and regular polyester back into its monomers so that they may be separated and used again to create new fibers.
Agent for Processing
In the meanwhile, Teijin Frontier, the fiber and product conversion division of the Teijin Group, headquartered in Japan, has developed a method to remove polyurethane (PU) elastane fibers from polyester clothing that is being discarded.
The technique includes a novel processing agent that helps raise the caliber of recycled polyester fiber by being applied during the pretreatment stage of the chemical recycling process. The new process not only removes the elastane fiber but also extraneous elements like colors.
In order to broaden the reach of fiber-to-fiber recycling, the firm has been testing this technology since October 2022 and is collaborating with the supply chain to create a complete ecosystem that includes worn clothes collecting, sorting, and recycling.
The PU elastane fibers expand, their chemical connections weaken, and they disintegrate thanks to the new technology. The processing agent may be recovered and repurposed for environmental load reduction and system cost management. According to Teijin Frontier, recycled polyester materials produced using this technique may be used in the current chemical recycling process.
Method of Detection
Better recycling procedures are desperately required to deal with the enormous number of old textiles in an effective and ecologically responsible manner in light of the EU’s upcoming legislation on used textiles.
In addition to improving elastane detection and doing it in a more eco-friendly manner than before, TU Wien has created techniques that gently separate elastane while preserving other fibers. The secret is to choose the appropriate solvent.
The first step was to identify a quick and precise way to measure the amount of elastane in fabrics. They found via their investigation that there had never been a technique like this before, according to Boschmeier. The standard test procedure is quite time-consuming and employs a solvent that is deemed hazardous to health.
Now, a new elastane quantification instrument based on mid-infrared spectroscopy has been created to determine the true amount of elastane in a garment.
Non-Toxic Solvent
Finding a way to distinguish elastane from other fibers was the next task. The researchers from TU Wien conducted a theoretical study and tested with several solvents until discovering a safe solvent that dissolves elastane alone, keeping the reusable fibers intact.
A patent application has been submitted for the process that allows for the almost total recovery of materials like polyester or polyamide, including the recovery and reuse of the solvent itself.
Moreover, the separate parts of wool may be recycled when blended with polyester and elastane. Under gentle, safe circumstances, enzymes break down the wool to produce an amino acid cocktail that may be used in the fertilizer and cosmetics industries. The recyclable polyester is separated from the elastane in the next phase.
The textile industry has been using elastane to provide materials flexibility since the late 1960s. But XLance, which is pronounced excellence, is a relatively new polyolefin-based elastomer that stands out from conventional elastane’s polyurethane-based composition.
Costantino Colnaghi, chief executive officer of XLance, Novara, Italy, stated in a recent interview that this ensures that garments made with XLance maintain their stretch and performance for a longer period of time, underscoring the importance of durability in sustainability, especially in a world where more than 90% of textile waste finish up in landfills.
Furthermore, unlike the dry spin procedure for elastane, XLance employs a melt spin manufacturing mechanism. According to Colnaghi, the business has also made significant investments in R&D to improve the recyclability of clothing created using XLance.
NIR Sensing Technology
Used textiles are now sorted nearly entirely by hand. Sorting textiles according to fiber composition is essential for fiber-to-fiber recycling, which is presently the most sustainable method of recycling textiles. But with fiber mixes in particular, this cannot be done mechanically or with any degree of reliability by feel.
Using near-infrared (NIR) sensor technology, Annika Datko, a bachelor’s degree holder from the Institut für Textiltechnik at RWTH Aachen University in Germany, has shown how worn textiles may be sorted by fiber composition. When it comes to sifting worn textiles, this is still in its infancy, but it is already state of the art for recovering plastic trash.
In order for the procedure to function, a textile sample is exposed to NIR light. The wavelengths of the reflected light that the detector detects may be used to produce a fingerprint-like material-specific spectrum.
Datko examined the spectra of materials made of various fiber compositions. She was able to demonstrate that, on a laboratory scale, the approach has an average mean error of just 4% and that it is feasible to distinguish between various fiber compositions using NIR.
