Net-Zero Materials Transition: Polyester

As the fashion industry strives to become more sustainable, the focus on polyester (aka PET) is inevitable. With a global annual production volume of around 63 million tonnes, polyester is incredibly popular due to its durability, affordability and versatility.

This article explores the environmental impact of the production and lifecycle of polyester and questions how we can transition this widely-used fabric to a net-zero material.

What is Polyester

Polyester is a synthetic fibre known for being cheap, washable, and resistant to wrinkling and fading, all qualities that enhance its popularity.

The fabric polyester is made from fibres and yarn derived from petroleum. Its proper name is polyethylene terephthalate (PET), in other words, polyester is a type of plastic.

This means that, unlike natural fibres, such as cotton, polyester is not dependent on land, farming, harvesting, weather and climate etc. However, as we are about to uncover, this doesn’t make it a ‘green’ material. And yet, as a plastic, it does mean that there are opportunities for recycling and reuse in a multi-faceted way.

Why Focus on Polyester for Net Zero Material Transition?

According to the textile exchange materials market report, published in December 2023, polyester is the most widely produced fibre globally, accounting for 54% of production in 2022.

However, with its production being derived from petroleum, it is one of the most energy-intensive and environmentally damaging processes in the textile industry.

Given the significant negative environmental impact of polyester production and the pressing demands of upcoming EU legislation, retailers must ask: how can we transition this familiar yet complex material towards a sustainable future?

The Problem with Polyester

The major problems are

• greenhouse gas emissions,
• microplastic pollution,
• resource consumption in production,
• and in disposal, heavy reliance on landfill and incineration, which again leads to carbon emissions.

The polyester production process

As polyester is a synthetic fibre manufactured from petrochemicals, its production is reliant on fossil fuels. Annually, its production requires 70 million barrels of oil.

This process causes significant greenhouse gas emissions, contributing to climate change.

For instance, the production of a polyester shirt releases more than double the amount of CO2 compared to a cotton shirt (5kg of carbon dioxide compared to 2.1kg)

Polyester and microplastic pollution

Another major problem with polyester is microplastic pollution. When washed, polyester garments shed tiny plastic fibres that can end up in waterways and oceans, posing a threat to marine life and potentially entering the human food chain. A single wash of a polyester shirt can release up to 4000 microfibres

Moreover, polyester is not biodegradable, which means it can persist in the environment for hundreds of years if not properly managed. A polyester garment could take up to 200 years to disappear completely.

Microfibres are shed through wear, as well as washing and drying clothes. Polyester fleeces are seen as some of the worst shedders. There isn’t a great deal clothing manufacturers or retailers can do to reduce microfibre shedding, except by avoiding synthetic materials like polyester altogether. Read on for innovations around microfibre capture.

Polyester and disposal

The UK produces over 300,000 tonnes of polyester textile waste every year. Used textiles are either thrown into landfills, incinerated on a large scale or sent to used clothing markets, often overseas and even ending up in landfill sites in Africa.

The urgent question now is whether polyester can transition to a net-zero material through the adoption of circular design, advanced recycling technologies, bio-based alternatives and innovations in the manufacturing process.

What are the Options for a Sustainable Future?

Recycled Polyester or rPET

rPET, is made from recycled plastic bottles and textile waste. Using rPET reduces the dependency on virgin petrochemicals and lowers greenhouse gas emissions.

At the Retail Supply Chain Sustainability Conference (RSSC) in March 2024, Professor Kate Goldsworthy, from the Centre for Circular Design, UAL, highlighted many practical examples of how fully recyclable clothing is already being achieved, for instance, by processing vast batches of waste clothing into R-PET pellets for reuse.

However, in spite of these advancements, according to the Textile Exchange, recycled polyester constituted only 13.6% of global polyester production in 2022, down from 14.8% in 2021. This indicates there is still significant progress to be made.

Why don’t we recycle all our polyester clothing then?

One issue with recycling is that the process can be energy and time-intensive, partly because not all polyester products are currently recyclable. In clothing, fabric composition may not be simply polyester, even if the care label says 100% polyester. Business Trading Standards states:

“Any decorative matter that makes up 7% or less of the product is excluded from the indication of fibre content.”

In addition, most garments have add-ons to the base fabric as well. For example:

• Other fibres – elastane, metallic threads
• Sewing threads
• Hard trims – zips, buttons, poppers
• Labels
• Construction materials – interfacings
• Decoration – Embroidery, applique
• Coatings finish – Anti-bacterial, water-resistant
• Print

In order to recycle PET polyester easily then trims or fittings, like elastic waistbands, metal zips, and labels have to be removed. This adds to sorting and pre-processing before any recycling can occur.

To help make polyester clothing more easily recyclable, garment designers and manufacturers should increase their considerations around circularity at the design phase to minimise the use of additional fabrics or ensure a path to recyclability.

There are of course compromises in this, as polyester blends, such as polyester-cotton, are attractive because they increase comfort and breathability, it can also better handle frequent washing. 100% polyester has a reputation for producing static, feeling clingy and stuffy to wear, due to its low absorbency.

But, when 100% polyester is possible, minimal redesign can substantially reduce the number of garments going to landfill. Prof Goldsworthy highlighted the school wear brand, David Luke, which, working with the Circular Textiles Foundation, created a range of recycled school wear designed to be recycled.

Without changing the aesthetics of their school blazer design, and with minimal redesign, the Eco-blazer saved:

• 340,000 garments from landfill
• 170,000 kgs polyester
• And 536,211 kgs of CO2

While transitioning to recycled polyester can significantly reduce carbon emissions, with some initiatives showing reductions of up to 80%, it does not completely eliminate them. Similarly, research into Project Plan B polyester recycling based in Kettering, UK, showed a significant carbon and cost reduction for the production of textile-to-textile rPET in comparison to virgin polyester.

Combining rPET with the EU DPP

For retailers, it’s important to make waste garment collection easy for consumers, preferably either returning to the shop or the organisation in the case of work or school uniforms for recycling. The information listed on care labels is crucial to communicate how to recycle the item and will ideally form part of the EU Digital Passport for apparel.

Advanced Recycling Technologies

“The used-textiles-to-yarn industry is set for rapid expansion as legislation and consumer pressure combine to force major retailers to act.” The Guardian, May 2024

So, what can be done to help recycle more polyester?

On a more positive note, the Autosort for Circular Textiles Demonstrator (ACT UK) led by the UK Fashion and Textile Association is midway through a project to scale and systematise polyester recycling for commercial use. Its goal is to develop and pilot the world’s first fully integrated, automated sorting and pre-processing plant for waste textiles. By utilising state-of-the-art technologies such as optical scanning, robotics and pre-processing (removing buttons, zips etc.), and artificial intelligence, the aim is to reduce the cost and manual labour involved in sorting and pre-processing clothing and bedding etc. before they can be recycled.

What can we do about ‘contaminated’ polyester

Polyester which has been treated to a coating, e.g. waterproof, or which has been printed with inks/dyes, is not immediately suited to recycling into rPET. Similarly, clothing which is embroidered, beaded, or sequined clothing cannot be recycled. At present there isn’t a commercial answer to these major challenges, but read on to discover what’s in the pipeline.

What can we do about polyester blend fabrics?

At the vanguard of recycling technologies is chemical recycling. In 2023 US researchers at North Carolina State University identified a method to break down polyester-cotton into its component parts within 48 hours. The same year in Demark at the University of Copenhagen another team of researchers found another chemical approach that leaves both the PET and cotton intact. Both result in a polyester product that can be reformed into pellets and from there, recycled yarn. Both may help pave the way for large-scale chemical recycling and the upcycling of blended composites and PET-containing waste, although there is work to be done to create a commercial, fast recycling process.

These technologies may be able to handle mixed fibre fabrics and contaminated materials, which traditional mechanical recycling cannot.

By increasing the collection and recycling rates of plastic waste and improving recycling technologies, the textile industry can make significant strides towards making recycled polyester more prevalent and effective.

And by investing in and scaling up these technologies from end-to-end, and considering circularity at the design stage, it is possible to envisage a textiles industry which has a closed-loop system for polyester production and use.

Bio-Based Polyesters

Another way to move towards net-zero polyester is by using bio-based polyester. These are a class of polymers derived from renewable resources, such as plant-based oils and fats, instead of fossil fuels.

This alternative has the potential to reduce the carbon footprint of polyester production significantly.

Although the production of bio-based polyester is still in its early stages, it’s expected to increase significantly over the next decade. In 2022, the global bio-based polyester market had reached 2.1 million dollars and is expected to reach 9.6 billion dollars by the end of 2032.

However, the production of bio-based polymers is generally more expensive than traditional polyester. This is due to higher raw material costs and developing technologies. The production processes for bio-based polyesters are still being optimised and scaled up, which increases costs.

There are also concerns about the land and water use required to grow the raw materials, which need to be managed sustainably. As always with the net-zero challenge, there are no easy or simple answers. Every alternative has its environmental consequences.

Green Innovations in the Production and Use of Polyester

Growing awareness of the environmental impact of polyester production has prompted manufacturers to adopt more sustainable working practices, and this is an area that brands and retailers can consider when sourcing their supply.

Here are some key initiatives currently transforming the industry.

Improvements in Energy and Water Efficiency

Innovations in the production process aim to reduce energy and water usage. For example, traditional dyeing processes in polyester manufacturing are highly water-intensive, often leading to significant water pollution and waste. New waterless dyeing techniques, such as supercritical CO2 dyeing, eliminate the need for water, offering a much more sustainable solution.

Renewable Energy Sources

Some polyester manufacturers use renewable energy sources like solar and wind power in their production processes. This shift significantly lowers greenhouse gas emissions which are typically high in traditional polyester manufacturing.

3D Printing

Advanced 3D printing technologies are being explored for creating polyester-based products. These technologies can lead to more precision in production, therefore reducing waste and material consumption.

Enhanced Performance Characteristics Using Nanotechnology

Enhancements using nanomaterials improve the strength, durability, and functionality of polyester fibres. This could help garments last for longer.

Microfibre Capture Technology

To help prevent PET microfibres from being released into the environment, particularly waterways, there are some options available to consumers to capture microplastics in laundering. Unfortunately, these are not owned by clothing manufacturers, but it might be something they could sponsor or endorse.

Washing machine filters

Washing machine manufacturers have developed in-built filters on new models, or a more affordable option is to buy a microplastic filter that fits onto existing washing machines.

Microplastic laundry bags

Another cheaper option is for consumers to place synthetic materials into separate microfibre capture laundry bags, before putting them into the washing machine to help capture microplastics.

Can Polyester Ever Be Net Zero?

Realistically, producing cheap new polyester is not going to be a net zero process. It will inevitably require fossil fuel extraction and production and emit greenhouse gases, so until a bio-based alternative can be produced at a commercially competitive cost, the best option is to focus on recycling, improving durability and switching to green energy supply in the production process.

How to Transition to Sustainable Polyester

Transitioning to sustainable polyester is a long-term commitment that requires dedication, collaboration, and a readiness to embrace change. This is not just a supply chain traceability problem, it’s a strategic commercial, design and product life-cycle challenge! Every business will have a view of the goals and targets they want to achieve, but there will be certain steps required to get a grip on polyester-related carbon output.

Evaluate PET in your supply chain

Begin by thoroughly reviewing your supply chain and tracing polyester orders and suppliers.

You’ll be looking to quantify how much 100% PET you’re ordering now, and calculating the carbon output of this production from your suppliers. Identify areas where carbon output could be reduced in the production process, by switching to green energy, for example. Segura has the capacity to help you capture and assess this data to benchmark it with your suppliers’ support.

It will also be essential to capture any rPET suppliers if you have any. The aim will be to transition to rPET if possible.

Finally, you need to look at polyester blend fabrics, as these are currently not recyclable, the ‘green’ aim would be to reduce their production.

Get a vision for circular design

A transition to sustainable polyester requires a vision for circular design, where product designers receive training and ideas about how to move to sustainable polyester and considerations they can make in the design process. The Circular Textile Foundation provides such training and guidance. This also opens up opportunities for marketing, without the risk of greenwashing. For example, a product range of recycled and recyclable clothing.

Sourcing and partner decisions

In order to create a closed-loop polyester production, then your buyers need to connect with the right suppliers and partners.

Depending on how you want to approach this, it may be that you will be simply switching to source rPET instead of PET. Or it may be that you want to engage in a fully circular model, where you will be collecting and supplying PET feedstock into a recycling facility to then recycle. Either way, you should look to verify supply and confirm your sourcing routes.

Identifying feedstock for recycling

There are several sources for PET ‘feedstock’ (in other words polyester clothing, bedding that can be broken down and reformed into rPET pellets).

• Deadstock - samples, unsellable goods, or returns? Do you or your suppliers have warehouses for polyester fabric that is not being used? Can this be transported to a recycling facility?
• Commercial customers - do you supply polyester products on a large scale to commercial customers, e.g. work uniforms, school uniforms, bedding for hotels etc., and can this be collected and recycled at the end of life?
• Clothing design to be recycled - can you collect polyester products from your retail customers for recycling at end-of-life?

Care label (digital product passport) for laundry and recycling guidance

Engage with your customers to build a community of eco-conscious shoppers. With material transparency and carbon data in hand, you can communicate your sustainability efforts with your customers. The Segura Digital Product Passport solution enables you to print a QR code on a care label that links to a relevant product care webpage. This can provide useful information about how to care for your polyester products in the most environmentally friendly way (e.g. using a microplastic filter or laundry bag when washing). It can also tell consumers how to recycle their product at end-of-life.

Longer term greener solutions in PET production

Adopt innovative practices such as exploring bio-based alternatives, and innovative manufacturing technologies to minimise environmental impact. Consider the entire product life cycle and develop circular practices to promote sustainability.

The rewards of these efforts are substantial: a healthier planet, a loyal customer base, and the satisfaction of leaving a lasting legacy of sustainable practices and environmental responsibility.

How to Transition to Sustainable Polyester?

Transitioning to net zero with any product or component is a long-term commitment. It requires time, dedication, collaboration, and a willingness to adopt new practices. Established users of Segura have found that focusing on a few significant metrics initially and working with suppliers on these areas can bring about measurable change.

Take a closer look at your supply chain: Review your current practices. Supply chain transparency and traceability are crucial in identifying the best routes to improvement. Partner with responsible polyester producers, manufacturers and recyclers to build ethical, sustainable, and innovative practices.

Introduce solutions for a greener future: Adopt innovative practices, and look at ways to build circularity into design along with alternative materials to minimise environmental impact. Consider the entire product life cycle.

Engage your customers: With transparency and data, you can showcase your progress. Develop strategies to communicate your sustainability efforts, building a community of eco-conscious shoppers.

The rewards are vast – a thriving planet, a loyal customer base, and the satisfaction of leaving a lasting legacy of sustainable practices and environmental responsibility.

Read more on Net-Zero Materials Transition in the Fashion Industry, or take a deep dive into another fabric here:

Net-Zero Materials Transition by Fabric

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