A fine line
Advancements in recycled cotton ring yarns for knits unveiled at ITMA are likely to inspire a sizeable ripple effect.
Major news from recycled cotton fibre and blends producer Recover, based in Spain, Swiss textile machinery developer Rieter and Portuguese spinning, weaving, knitting and finishing specialist Polopiqué at ITMA in Milan in June centred on an important industry breakthrough: the doubling of recycled fibre content in fine ring-spun cotton yarns from 20% to 40%. The recycled fibres used are from post-industrial cotton fabric scraps, processed by Recover in Banyeres de Mariola via mechanical means.
It has long been tricky to manufacture quality ring yarns from heterogeneous, recycled raw material with high short-fibre content, explains head of sales and marketing for Rieter’s machines and systems business, Franziska Häfeli, to WSA. Compared to rotor-spun yarn, ring (or compact) spinning is more sensitive to the proportion of short fibres, she says, which has typically inhibited the extent to which recycled fibres, shortened through tearing and shredding, can be incorporated into blends. “There is a limit to how much the percentage can be increased,” concurs global technology support lead at Recover, Carlos Rico, “because the final yarn quality will drop drastically in terms of yarn imperfections and yarn strength”. He uses a 100% cotton ring Ne 30/1 yarn count with between 25% and 30% recycled content as an example, suggesting that, ordinarily, quality can begin to be “seriously affected” from this point onwards.
Therefore, recycled ring yarns usually contain around 20% recycled fibres at most, the long-standing collaborators, all well-known to the sportswear industry, say. The prevalence of virgin-fibre ring yarn in a textile and apparel market increasingly measured by sustainability metrics, however, convinced them to take up the challenge. They expect the market opportunity for recycled ring yarns will only broaden over time, in step with changing customer demand, local legislation and the resulting value chain impact.
The right ratio
Stronger, straighter and therefore smoother and softer, ring-spun cottons are especially well-suited to direct-to-garment, heat-transfer and screen printing, as they tend to provide a more even surface texture. The process of continually twisting the fibres together so tightly also makes for an especially durable textile versus rotor (open-end) spinning. Hence the significance of what Ms Häfeli calls the “rapid increase in unevenness and imperfections”, such as neps, that can become entangled with the fibres, as recycled content is added to blends.
Working together with Recover and Polopiqué, whose respective teams brought knowledge and experience of the latest mechanical recycling and yarn manufacturing technologies on board, Rieter turned to its Comber E 90 ring spinning machine, originally developed for producing as much as 100 kilos of combed sliver per hour. The company’s Compact Drum device was used in tandem. According to Ms Häfeli, this complete system, when used to spin a 50-50 blend of Recover-made recycled cotton fibres and virgin cotton, removes unwanted short fibres and neps, resulting in “significantly improved” levels of imperfections and unevenness. These shorter fibres or comber noil, the excess shaved off by the comber, are suitable for processing in Rieter’s rotor spinning systems. Returning to the ring spinner, the machine notably features “special components and settings” to further improve the yarn’s uneven qualities, she adds, as well as its own internal spinning stability and running behaviour.
Mr Rico describes their method as “a totally different concept of yarn spinning”. Combing the cottons made it possible to attain yarns of higher quality, which in turn made it possible to boost the proportion of recycled material in the blend. Taking away these shorter fibres, the main cause of yarns being less uniform and having lower tensile strength, made it easier to maintain a higher percentage of recycled fibre, even for yarns as fine as Ne 30/1, he states. In its initial experiments with Rieter, Recover trialled recycled and virgin cotton blends in a 50-50 ratio, as detailed above, but this amount was later toned down to “at least 40%”. The partners stuck to ring Ne 30/1 yarn count throughout. Ultimately, they landed on an Ne 30/1 compact yarn with “similar quality parameters”, especially in the areas of strength and tolerance for imperfections, to a ring Ne 30/1 carded yarn with 20% recycled fibre content.
Gaining ground
All this work is expected to open the door to increased recycled fibre percentages in ring yarns for knitted applications, “maintaining and even improving final fabric quality” for customers, Mr Rico continues. Having presented a “high-quality, sustainable” knit garment made from their co-developed yarn at ITMA, the collaborators will next seek to secure Global Recycling Standard approval for the process from Textile Exchange. For Ms Häfeli, the collective goal is to “make recycling mainstream” through scaled-up adoption.
Expanding on why, chief executive at Recover, Alfredo Ferre, framed their work on recycled cotton ring yarns as “spearheading a new era of sustainability” regarding environmental awareness and accountability when announcing their progress on the first day of ITMA.
That three such well-established industry players are now so enmeshed in an undertaking of this kind indicates how quickly the pace can pick up in the realm of textile innovation. It is important for ideas to be shown to be scalable, and thus commercially viable, outside of the lab, not just potentially impactful. As collaborations continue to form, evolve and begin to bear fruit, onlookers can only be encouraged as they witness how some sustainable textiles talk has roots deep enough to push past surface-level marketing hype, rendering certain investments capable of causing real disruption to the complex, less visible mechanisms that power today’s intertwined, interconnected and, of course, international supply chains.
Next on the agenda is securing Global Recycled Standard certification for the co-developed 40% recycled cotton ring yarns.
CREDIT: Ana Palacios
