Fiber Guide: Polyester

Guide

Fiber Guide: Polyester

October 13, 2021

As part of the CFDA’s extensive Sustainability Initiatives Resource Hub launched in January 2019, the CFDA operated an A-Z directory called the Materials Index. The Index was designed as an informational tool, focused on fiber knowledge.

The Materials Index listings migrated in to the CFDA.com Materials Hub and split traditional fibers from new-age innovative fibers/materials.

This series of resource guides are dedicated to ensuring designers have extensive knowledge on traditional fibers.

POLYESTER

Overview

Polyester is a manufactured synthetic fiber. It is a kind of plastic and is usually derived from petroleum. Alternatives to oil-derived polyester exist, including those made from recycled plastic, agricultural crops, or even waste.

Petroleum is a non-renewable resource and the petrochemicals industry has complicated social and political implications. Polyester generally has significant negative environmental impact during production, use, and disposal.

Polyester has often been considered more sustainable from a consumer care standpoint – polyester garments last a really long time and require less water, energy and heat for washing. But a multitude of recent studies show that polyester sheds small pieces of plastic called microplastics with every wash. These microplastics are filling our water and air, and are being ingested by marine life and animals and even us. While the full extent and impact of these microplastics is not yet clear, it is clear that the problem is huge (microplastics have been found all around the world) and could have detrimental impacts to plant, animal, and human health.

Polyester is the most widely used fiber in the world. It accounts for roughly half of the overall fiber market and around 80% of synthetics fiber, according to the Textile Exchange Preferred Fiber Materials Report 2017. In 2016, polyester fiber production is estimated at 52 million metric tons.

Benefits of polyester include durability, versatility, good sunlight resistance, light weight, resistance to wrinkles, resistance to stains, and quick drying time.

As Common Objective points out, polyester’s relative cheapness has fuelled the growth of fast fashion.

“Polyester is much (much, much, much!) cheaper than natural fibers and it wears like iron – so you can keep your sofa looking good for 30 years. The real question is, will you actually keep that sofa for 30 years?” – O Ecotextiles

“Unlike in the textile and apparel sector in general (where there are tens of thousands of manufacturers), in instances where textiles are directly connected to oil, ownership coalesces under the power of a few companies, mostly in terms of trademarks and patenting.” – Petrocultures: Oil, Politics, Culture

Sustainability Considerations

Not transparent

Good luck sourcing your polyester fiber back to its raw material source. We haven’t found any company that does (if you know of any, please let us know). Tracing back beyond the yarn producer is rare. Petroleum is one of the most difficult raw materials to trace back to the source. It’s worth noting that the top sources of crude oil are (in order): Saudi Arabia, Russia, the U.S., China, Iraq, Iran, and Canada. Some bio polyesters and recycled polyesters offer a more traceable supply chain.
“The chains of labour, natural resource extraction, and chemical production involved in the making of textiles and apparel are almost completely invisible in the final product. Entire systems are at work to keep things this way.” – Petrocultures: Oil, Politics, Culture
Suggestion: Start by asking questions of your suppliers. If everybody asks, the polyester supply chain could become more transparent in time. Choose recycled polyester or polyester derived from renewable resources (like biosynthetics) over virgin polyester.

Derived from non-renewable petrochemicals

Polyester is a synthetic fiber, but its raw materials still come from nature. Most polyester is made out of petroleum, a natural non-renewable resource. Right now, we’re using up petroleum much faster than it can be produced in nature. Some predictions indicate we could reach peak oil (maximum extraction) by 2030.
Producing plastic-based fibers for textiles uses an estimated 342 million barrels of oil every year, according to A New Textiles Economy Report 2017.
According to an article published in The Guardian in December 2017, fossil fuel companies are among those who have ploughed more than $180 billion since 2010 into new “cracking” facilities that produce raw materials for plastics. The new facilities – being built by corporations like Exxon Mobile Chemical and Shell Chemical – will help fuel a 40% rise in plastic production in the next decade.
Suggestions: Choose recycled polyester or polyester derived from renewable resources (like biosynthetics) over virgin polyester.

High Energy Use

Polyester requires high amounts of energy to produce.
According to CO, the energy required to produce polyester (125 MJ of energy per kilogram produced) and the greenhouse gas emitted (14.2 kg of CO 2 per kilogram produced) make it a high-impact process. In 2015, polyester produced for clothing emitted 282 billion kg of CO2 – nearly three times more than for cotton.
Suggestions: Use recycled polyester – 30% less energy is required to make shirts from recycled PET than from virgin polyester.

Highly polluting

In 2015, polyester produced for clothing emitted 282 billion kg of CO 2 – nearly three times more than for cotton, according to CO.
Water pollution is a big problem. During production, facilities producing polyester without treating wastewater have a high probability of causing environmental damage through the release of heavy metals, and toxic chemicals. The washing and disposal of polyester contributes to a significant amount of water pollution in terms of heavy metals, toxic chemicals, and plastic pollution (in the form of microplastics). Leaks or spills related to the extraction or transport of oil can also have detrimental effects on groundwater, oceans, and other water sources.

Lower water consumption than other fibers, but highly polluting

According to multiple analyses, water consumption in the production of synthetic fibers is lower than for natural fibers.
Suggestions: In many LCA analyses, polyester does better than many other fibers in terms of low water use. But make sure that your suppliers are not contaminating water and the environment. This can be challenging since very few clothing companies can trace their polyester back far enough to know where all sourcing, transport, and production is happening.

Dye process is generally better than for natural fibers.

According to the NRDC, polyester requires high temperature dying processes, but the process is shorter and requires less chemical use, making the overall impact lower than for fibers like cotton.
Suggestions: Choose more sustainable dyes and finishes.

Can be recycled and made out of recycled materials, but often isn’t

Polyester was one of the first fashion fibers to be recycled into a brand new fiber. Most recycled fibers are produced from bottle-grade, not fiber-grade, polyester. Recycled polyester requires significantly less energy to produce and creates significantly less environmental pollution than virgin polyester.
According to A New Textiles Economy Report 2017 (p37), “Less than 1% of material used to produce clothing is recycled into new clothing. This includes recycling clothing after use, as well as the recycling of factory offcuts… The majority of this recycling consists of cascading into lower-value applications such as insulation material, wiping cloths, and mattress stuffing. After being used in these applications, currently, the materials are difficult to recapture and therefore are usually discarded.”
Suggestions: Choose recycled over virgin polyester. Design your products for optimal recycling ability and create systems (for example, a take-back program) to ensure products get recycled.

Microplastics

It has been estimated that around half a million tons of plastic microfibers are shed into the oceans annually during the washing of plastic-based textiles such as polyester, nylon, or acrylic, according to A New Textiles Economy Report 2017
Suggestions: Avoid polyester and other synthetic materials.

Conflict materials

We don’t often think of polyester as a conflict material, but its main ingredient, oil, is a leading cause of war. Between one-quarter and one-half of interstate wars since 1973 have been linked to oil. Therefore virgin polyester could be considered a conflict material.

Potential impacts during customer use care

Polyester is resilient, has low absorbency, doesn’t wrinkle a lot in use, dries quickly, holds it’s form, and is pest-resistant. As a result, it requires relatively low impact care, less water and energy are required than for cleaning other types of fiber.
Unfortunately, the shedding of microplastics in the wash is a big problem as mentioned previously. Studies are currently underway to understand the problem and impacts on human, animal, and environmental health.
Suggestions: Design for less washing, washing in cold water, and air drying. Avoid dry cleaning. Be sure to educate your customers about best consumer care practices.

Not Biodegradable

According to CO, “As an oil-based plastic, polyester does not biodegrade like natural fibers. Rather it stays in landfill for several decades at least – and potentially for hundreds of years.”

More Sustainable Options

If you are going to use polyester, more sustainable options include:

Recycled Polyester

Using recycled Polyester reduces air pollution among other benefits. According to the Textile Exchange Preferred Fiber Materials Report 2017, recycled polyester makes up an estimated seven per cent of polyester fiber produced — these fibers are largely used in carpets, blankets, clothing and other textile applications.

Brands that make recycled polyester include:

Bionic
Eco Circle™ and ECOPET™ by Teijin
Econyl
EcoAlf
Ecofil by Wellman
Suprelle® by Advansa
Far Eastern TOPGREEN®
Fortrel EcoSpun
Hyosung Regen™
Indorama RAMA PET EA 60C
Libolon RePET™
Palmetto REPREVE®
Parley for the Oceans
Polartec Recycled by Maiden Mills
Polygenta perpetual
Poole Company EcoSure® and Bioplast™
RadiciGroup r-RADYARN®
RadiciGroup r-Starlight®
Sinterama Newlife™
Teijin ECOPET and ECOPET PLUS
Thread International Ground to Good™
Toray ECOUSE™ and CYCLEAD™
Unifi REPREVE ®

Bio Polyester

Visit Biosynthetics to learn more.

Bio Polyester is made from renewable sources such as bio waste or crops instead of PET or other petroleum sources. Biosynthetics are often considered a more sustainable option than virgin polyester, but it can get complicated. Sustainability issues with biopolymers can arise:

If the raw material used is not farmed in a sustainable manner. (For example, if it is made out of sugarcane, the environmental impact of growing that sugarcane). Biosynthetics can be more chemically intensive and polluting based on the fertilizers and pesticides used to grow crops and the processing needed to turn them into plastic.
If the raw material is a GM (genetically modified) crop.
If the biosynthetic material is not properly disposed of. Biosynthetics incorrectly disposed of in landfills or recycling facilities can cause environmental harm.

How It’s Made

There are many types of polyesters. Specific processes used by manufacturers vary and are proprietary, but the general steps of production include:

Petroleum forms in nature over the course of millions of years.
Petroleum is extracted from the earth with giant drilling machines and treated.
Petroleum is transported to refineries (by truck, ship, tanker, or pipeline) where heat, fuel, electricity, high pressure, solvents, and catalysts are used to break down the molecules into useful ingredients. This process is also referred to as “cracking”. Many petrochemical products can be derived from petroleum at refineries, but ethylene and p-xylene are the monomers used for the polyester production. Ethylene is then broken down even more using heating, cooling, pressure, water, and sometimes a catalyst to produce raw materials useful for polyester production, in particular ethylene glycol. The two main acids used in the production of polyester are dimethyl terephthalate (DMT) and terephthalic acid (TPA), organic compounds produced from P-xylene. Both DMT and TPA are stored in molten form and transported in tanks from refineries.
PET (polyethylene terephthalate, the same type of plastic used in plastic soda bottles) is formed through a process of polymerization in which ethylene glycol, TPA, and (depending on the process) DMT are combined using heat and high pressure. The result is a liquid of honey-like consistency that is extruded, dried, and chopped up to make plastic pellets.
To make polyester fibers, PET plastic pellets are melted and extruded through tiny holes called spinnerets to form long threads, which are then cooled to harden into a fiber. This process is called melt spinning. The shape and qualtity of holes can be altered to create fibers with different qualities. These fibers are twisted together to create polyester yarn and wound onto bobbins, where they are ready to be woven into fabric.

Available Standards & Certifications

The Global Recycled Standard (GRS) | The Global Recycled Standard is a holistic certification for products with recycled content. The desired effect of the GRS is to provide brands with a tool for more accurate labeling, to encourage innovation in the use of reclaimed materials, to establish more transparency in the supply chain, and to provide better information to consumers. The Global Recycled Standard (GRS) is an international, voluntary, full product standard that sets requirements for third-party certification of Recycled Content, chain of custody, social and environmental practices, and chemical restrictions. The goal of the GRS is to increase use of Recycled materials in products and reduce/eliminate the harm caused by its production. It is intended for use with any product that contains at least 20% Recycled Material. Each stage of production is required to be certified, beginning at the recycling stage and ending at the last seller in the final business-to-business transaction. You can see the full standard here.

Recycled Claim Standard (RCS) | The Textile Exchange RCS was originally developed in partnership with Outdoor Industry Association’s Sustainability Working Group’s Materials Traceability Task Force in 2013. It is an international, voluntary standard that sets requirements for third-party certification of Recycled input and chain of custody. The goal of the RCS is to increase the use of Recycled materials. You can see the full standard here.

OEKO-TEX® STANDARD 100 | A worldwide consistent, independent testing and certification system for raw, semi-finished, and finished textile products at all processing levels, as well as accessory materials used. The tests for harmful substances cover:

legally banned and controlled substances
chemicals known to be harmful to the health (but not yet legally controlled)
parameters for health protection

Taken in their entirety, the requirements go far beyond existing national legislation.

Fiber Guide: Polyester

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