From the Sector

With the aim to help the denim industry reduce the environmental impact of its wastewater and move towards circularity, Archroma, G-Star RAW and Advance Denim have renewed their joint commitment to the production of aniline-free denim apparel based on Archroma’s DENISOL® PURE INDIGO 30.

Their joint aim is to produce high-quality denim in authentic blue shades without the aniline impurity carried through from the synthesis of standard synthetic indigo. In traditional denim production, this aniline remains bound with the indigo pigment on the fabric; the remaining aniline is discharged during the dyeing and washing process. This can be a problem because aniline is toxic to aquatic life and two-thirds of aniline waste currently ends up in wastewater discharge where it could potentially pollute waterways and the ocean.

Archroma developed DENISOL® PURE INDIGO 30 to answer this key challenge. A 30% pre-reduced indigo solution, DENISOL® PURE INDIGO 30 makes it possible to produce indigo-dyed denim without aniline impurities throughout the process.

Easy to use with automated dosing, DENISOL® PURE INDIGO 30 reduces the water needed for preparation, washing and wastewater treatment compared to indigo grains. It also reduces hazardous chemical consumption while allowing high reproducibility and creating the authentic and iconic deep indigo shades traditionally associated with denim.

G-Star RAW is working towards making 20% of its entire collection from Cradle to Cradle Certified® fabrics by 2025. Its partnership with Archroma and Advance Denim contributes to this goal, since the aniline-free DENISOL® holds a Gold Level Material Health Certificate from the Cradle to Cradle Products Innovation Institute. DENISOL® PURE INDIGO 30 is also compliant with other eco-standards and the requirements of leading retailers and brands.

Advance Denim, G-Star RAW and Archroma have previously collaborated to launch collections based on Archroma’s EarthColors® technology, which upcycles plant waste from the herbal industry to create sustainable colorways.

Trützschler expanded their portfolio to become the first full-liner in the preparation of textile waste – from mechanical recycling to the spinning preparation of torn secondary fibers.

The TRUECYCLED solution is the result of their cooperation with the company Balkan Textile Machinery INC.CO. in Turkey, which they announced at the ITMA 2023 trade event in Milan. Since then, Trützschler has received many inquiries for recycling systems.

Success with a systems approach
Recycling systems face significant technological challenges. On average, torn fibers are much shorter than virgin fibers. The percentage share of short fibers in the fiber mass is much higher. Unopened yarn and fabric particles are also difficult to process. Not surprisingly, much academic and practical research is currently conducted to find solutions for these problems. Dr. Georg Stegschuster, a researcher specializing in textile recycling, believes a systems approach is needed. He is working at the Recycling atelier, a model factory for mechanical recycling in Augsburg, Germany, which is committed to delivering the latest technological insights for textile recycling. “A perfect fine-tuning between tearing and spinning preparation is key for obtaining the best possible quality results and avoiding unnecessary fiber shortening,” he says. “This can be achieved if you are in control of both processes – and have the necessary expertise for both processes too.”

Gentle but effective
In some cases, for example, it may be advantageous to have less aggressive settings in the tearing line. This can help avoid unnecessary fiber shortening. The remaining higher share of unopened fabric must then be handled in a high-performance spinning preparation line. This starts with the right blow room configuration for perfect opening, cleaning and blending. A card that is specially designed for recycling materials, such as the new TC 30Ri, can also enable gentle but effective treatment of fibers.

A shortened drafting process is also a must. The integrated draw frame IDF 3 can make this possible. The draft is high enough to provide excellent levelling of the numerous short fibers, but low enough to prevent floating fibers.

Full-liner in mechanical recycling and preparation of textile waste
Trützschler now offers a complete system covering the whole process, from cutting and tearing textile waste through to carding and drawing secondary fibers. Thanks to this holistic approach and Trützschler’s expertise for the whole process, manufacturers can avoid unnecessary fiber shortening.