Material efficiency and fiber recycling in textile spinning:approaches for circular economy

“From waste to value： Recycling processes in spinning preparation”

Dr. Bettina Temath， Christian Franke

Classification of textile recycled raw materials includes preconsumer and postconsumer. The former involves waste cotton from spinning preparation （which called soft waste） and yarn or garment production， and the latter includes used textiles/garments. These solid fiber composites. Fibers must be released from the fiber composite by tearing （hard waste）.

Different types of waste cotton require different recycling processes no matter soft waste and hard waste. For example， in yarn and fabric waste， lower short fiber content / longer average fiber length are more easier to dissolve； while in garment waste unused and used， higher short fiber content/ shorter average fiber length are harder to dissolve. Used clothes present the biggest challenge for recycling processes.

Recycling processes by waste type

Trützschler Spinning Preparation have blow room， draw frames， cards， combers， integrated draw frames. Further processing of recycling blowroom cotton waste： 1） Cotton spinning preparation line， e.g. through bale opener or exact dosing of waste through tuft blending system； 2） Rotor spinning machinery. The investment into a separate cleaning line for cotton waste quickly pays off due to raw material cost savings.

Example： 100 percent recycled denim （torn jeans）

The processing of 100 percent hard waste is possible， but adding at least 10-15 percent of carrier material acceler-ates production and reduces sliver breaks. Yarn counts up to Ne 30 can be achieved through increase of carrier material （e.g. PES）.

Importance of direct spinning with IDF

There are some requirements of carding technology as following. Specially developed webfeed area for optimum opening and cleaning of waste； constantly precise setting of carding gap for maximum quality and productivity； highly variable configurations and wire solutions for gentle， but effective treatment of short fibers； robust components ensuring reliable， high performance in all recycling applications.

A shortened drafting process is a must for the processing of materials with high short fiber content. Conventional processing through draw frames will result in high amount of floating fibers and false drafts. Special drafting zone geometry： Reliable fiber guiding and clamping to control floating fibers. Only one drafting zone to generate lower drafts： Avoid risk of false drafts and minimize resulting count variations.

“Efficiency in spinning regenerated fiber”

René Bucken， Saurer

Recycling has a long history in spinning mill， and increasing short fibre content brings challenges into spinning.

Ring mills often invested in a few rotor spinning machines to utilize comber noils and other short fibres resulting from the ring spinning process. Although this was maybe not originally called recycling， it was the first development step. Mechanical recycling has already been around a while as i.e. integrated mills have used cutting rests etc. Today mechanical recycling of pre- and post consumer waste is growing. Here the challenge lies in managing the high short fibre content in the spinning process. This influences quality of end products and fibres cannot be used unlimited times. Today man made fibres are already recycled manually i.e. bottle to pants. Considering the requirements of the future i.e. current EU targets， chemical recycling of fibres is expected to become the most efficient mass production also for non-MMF fibres. Chemically recycled fibres show similar characteristics to virgin fibres.

With Autoairo air spinning machine Saurer completes the circle of five end-spinning applications. Ring， compact， worsted ring， rotor and air spinning are all results of Saurers customer-focused product innovation. Automation and digitalisation are necessities in todays smart and connected world. Technologies for tomorrow s smart mill are developed today.

Saurers rotor spinning portfolio offers excellent features for processing a high short fibre content. Highest raw material utilization and special short fibre spinning features have made Saurer market leader in this field. Autocoro： the number one for automated spinning since 10 years with nearly one million spinning units worldwide. Saurer BD series semiautomatic rotor spinning machine has more than 0，5 million installed units processing recycled fibres， mainly in India， China and Turkey.

Ring spinning and recycled fibres： Z 72XL ring spinning frames – the modular allrounder

Processing recycled fibres in ring spinning is challenge by the drafting zone requiring certain minimum fibre length in order draft properly. Although ring frames can process almost all fibre types， higher short fibre content tends to result in higher number or yarn breaks and higher waste resulting in share of recycles fibres being considerably lower than in rotor spinning.

Currently we see the demand increasing and our textile laboratory is running tests for customers in order to optimize their processes. Features of Saurer Z 72XL offering flexibility and efficiency in processing recycled fibres： From fine counts with 36 mm ring & 180 mm tube length to coarse counts with 54 mm ring & 260 mm tube length and processing nearly all fibres such as cotton， polyester， polycotton， kevlar， recycled fibres. Automatic control and adjustment of spindle speed depending on the number of yarn breaks （OptiSpeed） for higher efficiency – especially useful in processing recycled fibres. High productivity， powerful and economical drive technology. Energy-saving technologies（TwinSuction and OptiSuction） for sustainable production. Quality determining Texparts drafting components ensuring best yarn results （i.e. weighting arm PK 2630 with numerous adjustments possibilities combined with top apron cradle）.

“New life for old clothes - Mixed fiber recycling for high demands”

Michael Wolf， Imat

Imat is a service company for OEM and suppliers， for automotive， plastics， and textile industries. It focus design and R&D of materials and components. And there are some international branches in Germany， USA， Mexico， China and South-Africa.

Every second， the environment of one garbage truck of textiles is landfilled or burned. Faced with mountains of unsorted textiles， we need to explore the boundaries of new materials. Thus the interreg project borns. Aim of this project is the use of unsorted， mixed fiber waste for anupcycling yarn development. Circular economy， CO2 reduction and protection of natural ressources strengthening of textile industry of rhine meuse north region， targeting the high volume automotive market.

In the case of workwear， first cut it to pieces as much as possible to get the metal parts such as buttons. Through several processes of cleaning， carding and respinning to get the cycling fabric.