High-Quality Yarn Made from Recycled Fibers

Doubling the proportion of recycled fibers in the yarn to 40 percent: trials at Rieter’s Spin Center in Winterthur, Switzerland.

As fashion brands commit to sustainability, the demand for recycled yarns continues to increase. Spinning mills are taking advantage of Rieter’s recycling technology and expertise to meet the growing demand. In this way, the principles of the circular economy are being introduced into the textile industry.

The perception of yarn as a commodity that can be produced cheaply and in any place is changing. To meet their own sustainability goals, global brands are increasingly focusing on the yarn production process. Spinning mills and their upstream processes are at the center of efforts to establish a circular economy in the textile industry. Intensive research is helping to improve the quality of yarns made of recycled fibers and the products made from them.

Technical innovation for mechanically recycled fibers

Recycled fibers will play an important role in the fiber mix of the future. In contrast to fibers from chemical recycling, fibers from mechanical recycling are already available for use in spinning mills today. In recent years, Rieter’s research has helped to improve the quality of yarns made from recycled fibers. Processing, however, continues to be a challenge. Residual, unopened yarn and fabric remnants, the high short fiber content and the high number of neps (fiber knots) reduce the quality of the end products.

New approaches for high-quality recycled ring yarn

The focus of current developments is on ways to improve the quality of fine ring and compact yarn from recycled fiber blends. The combed spinning process for blends of raw and recycled cotton allows for a high recycled fiber content while significantly improving yarn quality. Trials at Rieter’s Spin Center and with Rieter customers show that it is possible to double the proportion of recycled fibers in the yarn from 20 to 40 percent while halving yarn imperfections. The resulting noils can then be spun into recycled rotor yarns. The use of both spinning processes makes it possible to optimize the use of recycled fibers according to their fiber length, which is also very attractive from an economic point of view.

Strong partnerships for successful research

Rieter is working with fiber producers to better understand and optimize the spinability of recycled fibers. For chemically recycled fibers, the company works with Birla, an established viscose producer in India, and for mechanically recycled fibers with Recover, a producer of recycled cotton fibers based in Spain. Rieter collaborates with ETH Zurich on research into recycling technologies. The company is researching the subject of the ecological footprint in conjunction with the German Institute for Fiber Research in Denkendorf.