Why Polyester-Cotton Blends Must Be Split Before Their Fibres Can Be Reused

Textile-to-textile recycling turns used textiles back into new materials. Two broad routes do this. Mechanical methods work on the material physically, while chemical methods dissolve or separate its fibres. Single-fibre garments are the simpler case, and blends are harder to recycle.

Polyester-cotton blends show the problem most clearly. Each fibre needs a different treatment, and in a single fabric the two are held together. Before either can be reused as fibre, a recycler has to split them. The methods for doing so are at different stages, from university research to a plant still in planning.

Mechanical Recycling Works Best on Single-Fibre Garments

A Textiles.org article on separating cotton and polyester says single-fibre cotton or polyester is easy to recycle. The same article says mechanical separation does not work for blends, because the two fibres are tightly bonded in the fabric.

A single-fibre garment has one material to recover, while a blend has two. A recycler has to pull both fibres apart, and a physical route cannot do that for a blend.

The fibre content of a garment therefore affects how easily it can be recycled. The chemical routes in the next section dissolve one fibre so that the other can be recovered.

Circ’s Saint-Avold Plant
Circ’s planned plant in Saint-Avold, France, would process 70,000 metric tonnes of poly-cotton textiles a year at full capacity, with full operations targeted for 2028, according to Textile World.

Chemical Routes Dissolve One Fibre to Free the Other

Deakin University researchers have described a process that uses an ionic liquid, a salt in liquid form, as the solvent. The solvent dissolves the cotton. The dissolved cotton is then regenerated into fibre, and the salt solution is recycled back into the process.

The polyester that remains can be melted and reshaped into fibres or plastics. The Textiles.org article says ionic liquids are more environmentally friendly than the chemical solutions commonly used to dissolve polyester, and that earlier chemical separation methods had practical and environmental drawbacks. It presents the environmental comparison as its own claim, without supporting data.

The researchers say the process can also be applied to recycling any type of biocomposite material. It adds that regenerated cotton is growing in popularity as a precursor in the carbon fibre industry.

Circ takes a different route. The company describes its patented technology as hydrothermal and says it separates polyester and cotton from polycotton blends and recovers both. The ionic-liquid process recovers cotton and leaves polyester for reuse, while Circ’s description covers recovering both fibres.

Circ’s Planned Saint-Avold Plant and Its Timeline

Textile World reported in May 2025 that Circ plans a plant in Saint-Avold, in France’s Grand Est region. At full capacity the site would process 70,000 metric tonnes of poly-cotton textiles a year. The report gives an investment figure of €450 million.

Construction is scheduled to begin in late 2026, as permitting allows, with full operations targeted for 2028.

Textile World says the recovered polyester and cotton are intended as high-quality raw materials for the textile industry.

Net Zero Compare describes the technology as separating the polyester from the cellulose in polycotton waste. These recovered materials can then be processed into new polyester and cellulosic textile inputs.

Textile World says polyester and cotton together make up 77% of the global textile market.

Primark’s Multi-Year Deal Targets 2029 Use in Clothing

On 1 October 2026, Net Zero Compare reported a long-term partnership under which Circ’s recycled polyester is expected to enter Primark clothing at scale from 2029. The report describes it as the retailer’s first multi-year offtake agreement with a textile-to-textile recycling company.

The partnership covers recycled polyester made from textile waste. The companies have not disclosed the financial value of the deal or the volume of material Primark has committed to buy. The same report says Circ’s technology is particularly focused on polycotton, a blend of polyester and cotton that is widely used in clothing.

The planned commercial plant will source feedstock globally, including textile waste from Europe.

The report places the start of Primark’s use in 2029, one year after the 2028 full-operations target for the Saint-Avold plant.

A single-fibre garment has one material to recover, while a blend has two.

EU Rules Set Producer Fees for Textile Collection

The EU’s revised Waste Framework Directive entered into force on 16 October 2025, according to the European Commission. It sets common rules for extended producer responsibility, and under its textile and footwear rules, producers pay a fee on each product they place on the market.

The fees finance collection schemes and the management of collected textiles, including re-use, preparing for re-use, recycling and disposal. They also fund consumer information on sustainable textiles and footwear, and research into product design, waste prevention and waste management.

Fees can be adjusted using sustainability criteria such as durability and recyclability, a process the Commission calls eco-modulation. Social economy enterprises in second-hand textile collection are exempt from these obligations and can run their own collection systems.

Separately collected textiles must be sorted before any possible shipment.

The Commission says Member States have 20 months to transpose the directive and 30 months to set up textile EPR schemes. Counted from 16 October 2025, those periods end in June 2027 and April 2028.

What Recycled-Content Claims Must Show in the U.S.

The FTC’s Green Guides, at 16 CFR 260.13, say it is deceptive to represent that a product contains recycled content unless the material was recovered or diverted from the waste stream. The material can be pre-consumer, from manufacturing, or post-consumer, from use.

A claim that includes pre-consumer material should be backed by evidence that the material would otherwise have entered the waste stream. Marketers may leave the two types unlabelled. If they distinguish between pre-consumer and post-consumer material, they should have substantiation for any claim about the percentage of either type.

An unqualified recycled-content claim is allowed when the entire product or package, apart from minor incidental components, is recycled. A partly recycled item should have a clear and prominent qualifier giving the percentage by weight. The rule gives an example of acceptable wording that states a 50 percent recycled-fiber figure.

Under that rule, a poly-cotton garment with recycled polyester and virgin cotton falls into the partly recycled group.

Photo: NASA/Desiree Stover · Public domain · via Wikimedia Commons