Circular Materials for Sustainable Swimwear

Models wearing RubyMoon navy swimsuits standing on paddleboards at sea
RubyMoon Gym to Swim is on a mission to reduce global oil demand by using synthetic textile waste in a circular swimwear material. Image: RubyMoon Gym to Swim

Millions of tonnes of post-consumer textile waste is sent to landfill worldwide every year. Much of this is made from synthetic materials such as polyester, nylon and elastane – plastic-based materials that increase global oil demand. Only a tiny proportion of textile waste is recycled into new products, means demand for virgin materials remains high.

Swimwear poses a particular challenge. To give each garment stretch, elastane is usually added along with nylon filaments, but the difficulty of separating these different polymers makes these all-synthetic garments very difficult to recycle. With support from Future Fashion Factory, RubyMoon Gym to Swim is seeking to address the double challenge of waste and demand for new materials by developing a fully circular advanced material.

“Vast quantities of nylon end up in landfill every year, and we needed the technical help to see how we could turn waste into a resource,” says Jo Godden, founder of RubyMoon. “We’d been thinking about how to close the loop in our manufacturing for a while, but we had no idea how to go about it.”

Jo began collaborating with Dr Muhammad Tausif (Tausif) and PhD researcher Rebecca Cooper at the University of Leeds to lay the groundwork for a longer journey into circular synthetic materials for the swimwear market. As Associate Professor in Sustainable Textile Manufacturing, Tausif’s technical expertise enabled the project partners to probe the specific challenges of analysing and processing textile waste.

“Sorting and separation is always the challenge with multi-component materials,” he explains. “That makes working with waste very complex, but there is so much of it in the world that we need to find innovative solutions for it.”

Atlanta Cook wearing a RubyMoon long-sleeved top and shorts, crouched on a surfboard at sea
Atlanta Cook, marine environmental consultant, photographed wearing RubyMoon made from Econyl, a fabric made from recycled marine plastics. Image: RubyMoon Gym to Swim

The project set out to analyse the existing materials and manufacturing landscape, identify the challenges that will need to be addressed to bring a viable product to market, and set the direction for the next phase of development.

The materials challenge across the sector was evident from the beginning, when RubyMoon called on its network of customers and local businesses to crowdsource samples of old swimwear. Unclear and inaccurate labelling meant the component mix was often more complex than expected, while the process of manually sorting through garments highlighted the need for automation. Similarly, the project raised the importance of having specialist equipment in the UK that can separate synthetic fibres.

Katie Rood wears a RubyMoon navy top and shorts with a blue football under her foot.
Katie Rood, professional footballer for Lewes LFC, wears RubyMoon made from Econyl. Image: RubyMoon Gym to Swim

“There’s a lack of transparency in the industry and no way of verifying the materials before sorting through and analysing them individually,” says Jo.

“It was helpful to realise that we will need to be able to guarantee the materials we are working with before we start processing them to make a new fabric, and then ensure we have the infrastructure to do it in the UK at scale.”

By combining physical sorting and separation of materials, extensive desktop research and a variety of lab-scale experiments, Jo, Tausif and the wider team developed a clear plan of action to eventually bring a circular material to market.

The next stage of the journey involves a larger project, building directly on these findings to address these challenges, test the manufacturing process and pave the way for a prototype recycled fabric.

RubyMoon is focused on enhancing the sustainability of its swimwear offering, but the project team sees the impact of their current journey being felt across the sector.

Multi-component materials are ubiquitous and the difficulties of separating fibres can make recycling synthetics economically unviable. New approaches to recycling synthetics could therefore increase the proportion of textiles being returned to the value chain – creating a circular economy that reduces the demand for resource-intensive, virgin synthetics.

“This is the way we have to go as an industry,” Jo adds. “Circularity and end of life has to be central to anything new we develop.

“What we’re proposing is a full system change. We have to make that leap now.”