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Many end-users now expect recycled materials to be in textile products they purchase – and this is driving innovation throughout the industry. However, there are still many technical and economic issues facing yarn and fabric producers using recycled resources. Members of the Swiss Textile Machinery Association offer some effective solutions to these challenges.

Synthetic recycled materials such as PET can usually be treated similarly to new yarn, but there are additional complexities where natural fibres like wool and cotton are involved. Today, there’s a trend towards mechanically recycled wool and cotton fibres.

Spinning recycled cotton
The use of mechanically recycled fibres in spinning brings specific quality considerations: they have higher levels of short fibres and neps – and may often be colored, particularly if post-consumer material is used. It’s also true that recycled yarns have limitations in terms of fineness. The Uster Statistics 2023 edition features an extended range of fibre data, supporting sustainability goals, including benchmarks for blends of virgin and recycled cotton.
In general, short fibres such as those in recycled material can easily be handled by rotor spinning machines. For ring spinning, the shorter the fibres, the more difficult it is to guide them through the drafting zone to integrate them into the yarn body. Still, for wider yarn counts and higher yarn quality, the focus is now shifting to ring spinning. The presence of short fibres is a challenge, but Rieter offers solutions to address this issue.

Knitting recycled wool
For recycling, wool fibres undergo mechanical procedures such as shredding, cutting, and re-spinning, influencing the quality and characteristics of the resulting yarn. These operations remove the natural scales and variations in fibre length of the wool, causing a decrease in the overall strength and durability of the recycled yarn. This makes the yarn more prone to breakage, especially under the tension exerted during knitting.

Adapting to process recycled materials often requires adjustments to existing machinery. Knitting machines must be equipped with positive yarn suppliers to control fibre tension. Steiger engages in continuous testing of new yarns on the market, to check their suitability for processing on knitting machines. For satisfactory quality, the challenges intensify, with natural yarns requiring careful consideration and adaptation in the knitting processes.

From fibres to nonwovens
Nonwovens technology was born partly from the idea of recycling to reduce manufacturing costs and to process textile waste and previously unusable materials into fabric structures. Nonwovens production lines, where fibre webs are bonded mechanically, thermally or chemically, can easily process almost all mechanically and chemically recycled fibres.

Autefa Solutions offers nonwovens lines from a single source, enabling products such as liners, wipes, wadding and insulation to be produced in a true closed loop. Fibres are often used up to four times for one product.

Recycling: total strategy
Great services, technology and machines from members of Swiss Textile Machinery support the efforts of the circular economy to process recycled fibres. The machines incorporate the know-how of several decades, with the innovative power and quality standards in production and materials.
Stäubli’s global ESG (environmental, social & governance) strategy defines KPIs in the context of energy consumption, machine longevity and the recycling capacity in production units worldwide, as well in terms of machinery recyclability. The machine recyclability of automatic drawing in machines, weaving systems and jacquard machines ranges from 96 to 99%.

On the sidelines of the Intertextile Shanghai fair, the Swedish textile-to-textile recycling innovator Renewcell and the leading Chinese viscose manufacturer Tangshan Sanyou announced the next step in their partnership to make fashion circular that stretches back to 2018.

The two companies’ new shared ambition is to offer manufacturers and brands Circulose® viscose fibers made from 100% recycled textiles in commercial quantities starting in 2024. The collaboration has been facilitated by Ekman Group, Renewcell’s exclusive global trading partner.

“I am very happy to announce this acceleration of our long-standing partnership with Tangshan Sanyou. They were the first commercial producer of Circulose®-based fibers in the world, and the first to commit to sourcing significant volumes from us. Now, they aim to also be the first to commercialize 100% Circulose® content fibers” said Patrik Lundström, CEO of Renewcell, adding "I applaud Tangshan Sanyou’s vision and support to scaling next gen raw materials like Circulose®.”

The announcement, which follows the recent start of deliveries of 100% recycled textile Circulose® pulp from Renewcell’s newly opened Renewcell 1 recycling plant, is the result of successful validation of Circulose®’s quality in production at Tangshan Sanyou’s commercial-scale manufacturing lines. Tangshan Sanyou would strive to finish the mission of producing commercial volumes of 50% Circulose® content fibers during 2023 and work towards achieving the delivery of 100% Circulose® content branded viscose fibers to selected fashion brands and manufacturers starting in 2024. The two companies will cooperate to market the fibers globally using Renewcell’s Circulose® ingredient brand name.

Mr. Zhang Dongbin, Executive Vice General Manager of Tangshan Sanyou Chemical Fiber, says, "Through the collaboration with Renewcell, we have achieved to use Circulose® made from recycled cotton in the production of our viscose fibers, which is great beneficial to improving resource utilization efficiency and lowering carbon footprint of the industry. It has brought a huge impact in the sustainable fashion industry. We will continue putting efforts in forming good interaction between consumers, brands and enterprises, convey the concept of circular sustainable fashion, promote the greening of textile industry, and ensure a more sustainable way to ensure the sustainable development of the textile industry. Protecting the global ecological environment by applying sustainable solutions is our common goal."