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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%.

Comber machines from Trützschler are already trusted by customers across the textiles industry and around the globe. The TCO 21 is the latest addition to their portfolio and was built to boost productivity,  ensure quality and support increased automation.

High productivity and raw material savings
One of the key benefits of the TCO 21 is its advanced processing speed. This next-generation combing machine is able to produce at a rate of up to 600 nips per minute. the TCO 21 can also be coordinated with Trützschler’s JUMBO CANS (Ø 1.200 mm). They not only reduce yarn defects due to fewer piecings which leads to quality improvements, but also offer a higher efficiency because of their larger dimensions. This, for example, has positive effects on the number of necessary cans and can transports – and results in lower personnel costs.

Excellent yarn quality
The TCO 21 comes with COUNT MONITORING as standard. This feature makes it possible for the machine operator to define limits for count variations via an easy-to-use display. Trützschler’s DISC MONITOR system of sensors measures the count continuously, and the machine alerts the operator and switches off if the limit is exceeded. In addition, the COUNT MONITORING function also includes spectrogram analysis.

Customers can further strengthen their focus on quality by choosing to add the COUNT CONTROL function to the TCO 21. It is managed via the same easy-to-use display, and offers automatic sliver count measurement, as well as spectrogram analysis. It also automatically regulates the main draft during production to balance count variations and ensure the desired sliver count. This feature is particularly attractive for customers who manufacture blends of cotton and synthetic, as it can also be used to avoid variations in the overall yarn composition.

Automatic optimization
The TCO 21 joins the TCO 12 from Trützschler as an combing machine that offers automatic PIECING OPTIMIZER technology, and that finds the right piecing setting without a single laboratory test, because of two functions: First by adjusting the piecing time in the combing cycle (timing function). Whereas the resetting of the detaching point (piecing time) is usually a very time-consuming task, it now takes only a few minutes and is performed automatically at a push on a button. Second the customer is helped to select specific detaching curve types (curve function) for their unique requirements.

Easy operation
The TCO 21 is simple to operate and maintain. The SMART TOUCH display is fast and intuitive, and a Radio-Frequency Identification (RFID) sensor quickly identifies each user and adapts the information on the display to their individual needs. The multi-colored T-LED display provides visual indications of the machine’s status or quality parameters over large distances which enables the operator recognizing them at a glance in the entire spinning mill. The TCO 21 is built with original Trützschler electronics that ensure high performance and durability: Their intelligent cooling system, that has already proven itself in the draw frame TD 10, contributes to a longer service life by reducing the operating temperature of electronic power components. Even if components have to be replaced at some point, the customer can keep their spare parts inventory small, because they can switch also electronics spare parts flexibly between different machine types, e.g. cards and draw frames. The option to add an automatic greasing function completes the easy operation of the TCO 21.