From fibre to fibre: Polyester textiles recycling

In the absence of clear signposting or legislation, such as the Strategy for Sustainable and Circular Textiles being developed in the EU, the UK public is largely confused as to where is best to dispose of waste textiles – and what types of textiles can be reused or recycled.

The issue of sorting and separating textiles extends to the industry itself too. The textile waste stream is comprised of many different types of material between cotton, wool, synthetic fibres and so on – all of which need to be sorted for different recycling techniques. Progress in the area of sorting is being made through novel sorting methods, such as the infrared technology ‘Fibersort’ being developed and used by SATCoL – the trading company of the Salvation Army – which is able to sort ‘textiles by fibre type, blend and colour for recycling back into the circular textiles supply chain’.

Other projects, such as the Trace4Value initiative, are working to create Digital Product Passports (DPPs) for textiles which will increase traceability and transparency in the textile industry. The pilot is set to align with the EU textiles strategy which mandates the introduction of DPPs for textiles sold in Europe by 2030. This legislation will make it much easier to track and sort textiles based on their respective components.

However, tracking and sorting the different fabrics is just one part of the challenge – they then have to be recycled. Synthetic fibre ‘polyester’ accounts for 65 per cent of the global fibre market but there is yet to be any real use of textile-to-textile polyester recycling in the fashion industry.

But loads of brands sell ‘recycled polyester’ clothing?

There is a general misconception about polyester recycling – clothing items that are marketed as ‘recycled polyester’ are almost never made from other polyester textiles, but usually from other sources of polyester such as PET bottles.

Polyethylene terephthalate (PET) is the chemical name for polyester. After cleaning and sorting into respective colours, the bottles are shredded into flakes, melted down and extruded – a squeezing process – into plastic filaments. The filaments are then spun into a yarn which can be used to produce clothing. This is a mechanical recycling process which is relatively simple and used in many industries. Textile-to-textile polyester recycling requires a more complex process – chemical recycling.

Georgia Parker, Innovation Platform Director at Amsterdam-based Fashion for Good, explains: “The chemical recycling of textiles, as the name suggests, uses chemical processes to break down textile waste to a molecular level. The different outputs of chemical recycling offer multiple points of re-entry into the fashion supply chain and allow for a more versatile product range than mechanical recycling. Chemical recycling is also thought to increase the purity of the output products in comparison to mechanical recycling.

“Most of the recycled polyester on the market is actually made from plastic bottle sources rather than textiles. As such, the fashion industry is currently trying to ease the reliance on the bottling industry and push for circularity by investing in innovations in textile-to-textile polyester recycling.”

To summarise the problem, ‘recycled polyester’ is very different from recyclable polyester. Turning polyester fabric back into polyester fabric – i.e. textile-to-textile, fibre-to-fibre recycling –is yet to be deployed extensively in the fashion industry.

Projects looking to recycle polyester textiles at scale

Considered by many to be one of the key changes needed to make the textiles industry sustainable, there are many projects around the world trialling polyester textile-to-textile recycling at scale.

SATCoL’s Project Re:claim – a joint venture with Project Plan B – launched plans for the first commercial-scale, post-consumer polyester recycling plant in the UK this year. The exclusive textile-to-textile polyester recycling system uses a thermomechanical recycling process through what they call the ‘Thermo Mechanical Extrusion Recycler’ (TMER) machine and recycles polyester garments and offcuts into rPET pellets made from textiles. SATCoL installed the machine at one of its processing centres in Kettering which already sorts and processes around 65,000 tonnes of donated textiles every year. SATCoL says that the first trials, which began this September, will give it an understanding of how the quality of feedstock affects the output.

To maximise the volume and potential of the recycling process, SATCoL cannot rely on clothing bank donations alone and is calling for corporate partners to commit to donating 100 per cent polyester textiles. The project already has several retail and commercial customers, with many of the partnerships focused on the long-term goal of a fibre-to-fibre circular model. Commercially, it hopes to partner in the future with organisations that have excess polyester such as the NHS and the laundry industry which both use large amounts of polyester products.

Another project exploring the scalability of Polyester textiles recycling is the ‘The Full Circle Textile Project – Polyester’, which was launched at the end of 2021 in Amsterdam and expands on the work of the original Full Circle Textile Project. According to the company behind the project, Fashion for Good, the original project established a method of chemically recycling polyester which resulted in virgin-quality output which is applicable to a wide range of textile types. At the moment, however, the practice suffers a lack of financing, limited brand uptake, and low, expensive output that struggles to compete with cheaper virgin options. The next stage of the project will see a focus on the upscaling of these solutions. The project hopes to be able to share some of its findings early next year. Given stakeholder involvement, it is often impossible for these projects to share the exact details of their work.

Despite this, ‘The Green Machine’ project has been granted an open license by its founders, the Hong Kong Research Institute of Textiles and Apparel (HKIRTA), at cost price with no added margins. The project claims to have been the world’s first technology that could separate blended textiles at scale, without any quality loss. This is groundbreaking compared to Project Re:claim which still relies on 100 per cent polyester feedstocks.

In 2016, the H&M Foundation invested in the technology – a hydrothermal process that can fully separate and recycle cotton and polyester blends into new fibres and cellulose powder. A full-scale machine has been installed at a factory in Asia and has been running for the past three years. Well-known fashion brand Monki released the first collection made from the Green Machine technology in 2020 and a second collection this year.

Discussing why this kind of technology is not more widespread, Katherine Chan, Director of Business Development at HKRITA, told Resource: “The adoption of new technologies usually has a gradual pace, especially ones that entail a slightly higher cost. The last few years have been very uncertain for manufacturers, many individuals have adopted a wait-and-see approach.

“We remain committed to the promotion of the Green Machine. In fact, we are going to build a Green Machine in Hong Kong for industrial-scale trial in 2024.”

It’s a promising development and the H&M Foundation and HKRITA say that this open-source approach is key to reaching maximum impact and transforming the fashion industry. 

Wrapping up the polyester problem

With progress being made in discrete trials across the globe, it seems that there is hope for finding a solution to the problem of polyester textile recycling. With the right funding and partnerships, it may be that we see textile-to-textile recycling entering the mainstream in the next couple of years. The industry - particularly high-street brands which tend to have higher margins - will likely need to adjust to a period of inflated costs to make the economics work.

Fashion for Good believes that the solution to the lack of textile-to-textile recycling will likely need to be a combination of multiple factors, with brands or manufacturers willing to pay the price premium in the short term to enable these innovations to scale.

Speaking about the need for policy intervention, Innovation Platform Director Georgia Parker added: “Government policy and regulation also plays a major role in driving systemic change. Legislation and legislative requirements are putting increasing pressure on brands to know where their products end up and close the loop wherever possible.

“More is needed to provide a framework of policies and incentives that will drive systemic change. At the same time, the public sector must increase its direct investments and support to catalyse investment from the private and philanthropic sector.”

Ultimately, the technology is now undeniably available to recycle polyester garments – it’s up to stakeholders to keep applying the pressure to make sure brands invest at scale in trialling and then using it.