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Repreve LCA shows climate impact of recycled polyester vs. virgin polyester

By Simone Preuss


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Credits: Garment made with Repreve fibres. Image: Unifi

Repreve-maker Unifi announced the results today of a peer-reviewed Life Cycle Analysis (LCA) about the impacts of recycled polyester on climate change versus virgin polyester.

“Repreve significantly lowers the impact of climate change and will have an immediate impact on the sustainability goals and environmental footprint of our esteemed partner brands that integrate Repreve into their products,” said Unifi CEO Eddie Ingle in a press release. “We strive to be good examples of how to design for our planet and our future, so we are thrilled to be able to help others do the same.”

Repreve fibres made out of plastic bottles. Image: Unifi

Repreve recycled polyester

Repreve is Unifi’s recycled polyester brand made from post-consumer plastic bottles and pre-consumer waste materials. It is embedded with the tracer technology FiberPrint and verified by U Trust certification. To-date, Repreve has transformed over 35 billion plastic bottles into recycled performance fibre that is used by consumer brands like Ikea, Inditex, PVH and others.

The peer-reviewed LCA quantified the environmental impacts of Repreve across a variety of impact categories in comparison to virgin polyester and verified that Repreve lowers climate change impact. A virgin polyester baseline was established for each product to align with the same geographical production as the Repreve product.

While prior LCA data focused on Repreve DTY (drawn textured yarn) produced within the United States, the new study focused on a variety of products (Repreve PC DTY, Repreve Hybrid DTY, Repreve PC Staple Fiber) and global supply chains, namely in the US, Central America, Brazil, China and an additional Asian production site.

From recycled bottles to fibres. Image: Unifi

Comparison with virgin polyester

The global recycled polyester fibre brand explains the comparison with virgin polyester in an email to FashionUnited: “Virgin polyester data was prioritised from primary sources (where the data was collected from the producing site).Where primary data was not available, proxy datasets, as based on collected primary supplier data, were utilised that were representative of similar production sites in the same geography.”

“In the very limited cases where proxy supplier data was not available, representative datasets were utilised – in one case from Ecoinvent 3.7.1 database and in another from a published LCI. All primary and secondary datasets were modeled with Ecoinvent. The study was based on the International Organization for Standardization (ISO) 14040 and ISO 14044 and third party reviewed according to ISO 14044 following ISO 14071.”

According to the findings, Repreve significantly reduces climate impacts compared to virgin polyester, reduces greenhouse gas emissions by 42 percent and by 60 percent when compared to relative virgin staple fibre.

It also reduces abiotic depletion and fossil fuels by 66 percent (by 76 percent when compared to relative virgin staple fibre) and water scarcity by 76 percent and freshwater consumption by 67 percent.

Is using recycled polyester sustainable?

While using recycled polyester such as Repreve is better, environmentally, than using virgin polyester, the fact remains that polyester is a petroleum-based product whose dependence by the fashion industry should be phased out gradually in favour of non-petroleum-based fibres.

It is also a synthetic fibre with a host of advantages, especially for sportswear like being durable, abrasion resistant, quick drying, lightweight, strong and wrinkle resistant. However, there are a host of qualities that it lacks too, like not being very breathable, and having no anti-fungal, anti-bacterial, anti-microbial or healing properties like lotus, nettle or hemp fibres for example. Kapok fibres, mixed with cotton, have anti-moth, anti-mite and insulation properties that are comparable to down. Last but not least, polyester fibres are not biodegradable as 100 percent cotton or any other natural fibres would be.

While Repreve helps keep plastic bottles out of our oceans, fibres that use PET plastic bottles release microplastic fibres during the garments’ production process and when washed by consumers.

Last but not least, they also shift the focus from the main problem, namely that there is no system for the large-scale recycling of used polyester fabric into new textiles (yet). So while using fibres based on post-consumer PET bottles is a solution as long as there is an overhang of such materials, it can only be a temporary one while a truly sustainable solution in the form of polyester-to-polyster textile recycling is being developed and the use of virgin polyester fibres for fashion banned completely.