Polyester first emerged in mid 20th century, but it wasn't until the 70s when it hit the floors of disco clubs in the US. Tired of the formalities in the new corporate world, Americans fell for the casual laid back looks of the Leisure Suit. The kitsch style featuring funky patterns and contrasting colors quickly made it to Hollywood and soon became iconic in the influential disco culture.
Let's take a brief moment to appreciate the Bee Gees, ABBA, and young John Travolta in "Saturday Night Fever".
It is no coincidence that polyester became the fiber of choice in the defining times for modern music. In its early days, polyester was seen as a revolutionary material with unmatched qualities, destined to change the textile industry forever. And nowadays it is gaining popularity as a performance fabric when athleisure styles are becoming a staple in our fast-paced routine.
As of 2020, polyester accounts for 52% of all fibers - 57 million tons/year. At the current rate, this number is estimated to double by 2030.
What is Polyester Fabric?
Polyester is a category of polymer materials. They are naturally occurring compounds, and yet a lot of them are derived synthetically from crude oil. Polyethylene terephthalate (PET) is the most common type used in clothing and plastic manufacturing. It makes for 80% of all synthetic fibers and is also the most widely spread single-use plastic in the world - including drinking bottles, containers, packaging, etc.
Polyethylene glycol is the main compound used to create polyester. It is derived from non-renewable resources such as natural gas, coal, or as a by-product of petroleum refinement.
To form the polyester, a reaction (aka polymerization) between monomer alcohol and terephthalic acid is administered under high temperature (280°C). The liquid polymer is extruded through a spinneret, cut into chips/resins, and finally melted again to be spun into polyester yarn. This whole process is very energy-intensive due to the multiple cycles of heat generation and spinning.
Properties of Polyester
- Polyester is cheaper compared to natural fibers
- Unlike cotton, it doesn't shrink or lose shape
- The fabric lasts longer and is strong when dry or wet
- It is not prone to wrinkles, so ironing is not necessary
- Dries quickly after washing, because it doesn't absorb moisture
- It is stain resistant
- Polyester is unnatural - man-made/synthetic fiber made of plastic
- The material doesn't "breathe", so it traps heat and moisture
- Bacteria grow better on it, which can cause a bad odor
How Sustainable Is Polyester?
As we already discussed, polyester is usually made of petroleum, a non-renewable resource available in limited quantities. We can't sustainably produce it over the long term, especially at the current pace of consumption. Predictions show that we'll deplete our fossil fuel resources in the next 50 - 100 years if we don't take action.
Reducing the use of virgin plastic (and polyester) is one way to slow down the rate of resource utilization. Through circular economy and efficient recycling of materials, we will get a step closer to sustainable sourcing. But we are still far from it, with only 15% of textiles being put into use again and just 1% is used to actually make new garments.
For what is worse, probably a more immediate threat is the level of greenhouse gas emissions that are released into the atmosphere when we burn fossil fuels. Scientists raise concerns that reaching the tipping points of global warming can cause irreversible cascading effects that will push the climate system into a completely new state.
On the positive side, polyester clothes are generally easier to handle than most natural fabrics. Machine washing at low temperatures (30 - 40°C) generally works well. Tumble drying and ironing are often not necessary which is great for saving energy. On top of that, the fabric is very durable so you can wear it for many years and thus reduce your impact.
On the flip side, the fast fashion industry creates an incentive for people to constantly look for new styles and get rid of their clothing quicker. It is estimated that on average we wear garments only 7 times before disposal. That creates a whopping 92 million tonnes of textile waste each year.
Polyester is NOT biodegradable, so if not recycled it will remain in the ecosystems and will keep poisoning the environment, the ocean, and wildlife for hundreds of years. It is worth noting that we still don't have the technology to recycle plastics infinitely. With each cycle, the quality of the material degrades which makes it usable only for products of lower economic value - downcycling. And textiles are even harder to recover. For instance, common cotton/polyester blends are not eligible for mechanical recycling because it is impossible to separate the two fiber types. Such clothes are headed straight to a landfill at the end of their lifetime.
Finally, new research shows that synthetic materials like polyester also cause plastic pollution in the form of microfibers. Half a million tonnes of tiny plastics escape our homes every year. Often too small to be caught by water treatment plants, they get dumped into bodies of water and become part of the food chain. To mitigate this problem, we strongly recommend washing clothes at low temperatures and using a microplastics filter for your washing machine.
In summary, polyester is not sustainable because it is derived from non-renewable resources (oil), contributes to CO₂ emissions, and generates massive amounts of plastic waste and microfibers.
Impact: Polyester vs Cotton
Now that we know what are the environmental issues with virgin polyester, let's look into lifecycle (LCA) data and compare it to its notorious natural rival.
|Origin||Synthetic (oil)||Natural (plant)|
|Global Warming (CO₂-eq/1kg)||10.2 kg CO₂||9.3 kg CO₂|
|Energy Use (MJ-eq/1kg)||184 MJ||98 MJ|
|Water Scarcity (m³/1kg)||2.9 m³||124 m³|
|Water Pollution (PO₄-eq/1kg)||0.0031 kg PO₄||0.0167 kg PO₄|
The LCA data cited in the table represents example materials from the Higg MSI v3 tool. It is a cradle-to-gate fabric assessment including sourcing raw materials, yarn, and textile formation, preparation, coloration, and finishing.
- Polyester requires nearly 2 times more non-renewable energy to produce including oil extraction and manufacturing energy. On the flip side, energy is allocated to cotton in the cultivation phase from synthetic fertilizers and pesticides, irrigation, machine use, and manufacturing.
- Cotton contributes a lot more to water scarcity in arid regions growing the crop. Water pollution is also significantly higher because of phosphorus and nitrogen runoff from fertilizers.
- Cotton cultivation can cause soil degradation and destroy biodiversity, while polyester has the potential to generate a lot of solid waste and pollute water with microplastics.
- The CO₂ emissions are comparable and are mainly linked to burning fossil fuels for energy.
The verdict: Both Virgin Polyester and Conventional Cotton are unsustainable for different reasons. We don't have to choose one or the other. Ideally, we should be seeking better alternatives that address the existing caveats, such as recycled polyester and organic cotton.
Impact: Polyester vs Nylon
This is a more fair apples-to-apples comparison. Polyester and nylon share similar synthetic nature and are both known as performance fabrics because of their durability, resilience, and water resistance.
|Origin||Synthetic (oil)||Synthetic (oil)|
|Global Warming (CO₂-eq/1kg)||10.2 kg CO₂||16.2 kg CO₂|
|Energy Use (MJ-eq/1kg)||184 MJ||268 MJ|
|Water Scarcity (m³/1kg)||2.9 m³||2 m³|
|Water Pollution (PO₄-eq/1kg)||0.0031 kg PO₄||0.0044 kg PO₄|
Apparently, both fabrics have very similar shortcomings, but significantly more energy is required to synthesize nylon (polyamide) which also accounts for proportionally higher carbon emissions.
Clearly polyester can't be a long-term solution and neither are other mainstream fabrics. Then what can we tell about the future of the textile industry?
If I have to guess, it is unlikely that a silver bullet fabric will be invented any time soon. Of course, we should be seeking better alternatives, but a big part of the battle will be to improve on the materials we already use and love. For non-renewables like polyester, recycling is an effective solution to achieve sustainability.
What is Recycled Polyester?
Triggered by the concerns around the environmental impact of polyester, in 1993, Polartec and Patagonia collaborated to manufacture the first-ever polyester fleece from recycled bottles. Over the years, this idea has been popularised and replicated by big companies who wanted to attach a "green" label to their brands.
Recycled Polyester, also known as rPET, usually refers to a fabric made of post-consumer PET bottles.
Most rPET nowadays is created in a process known as mechanical recycling. In short, the used plastic first goes through multiple shredders that cut it into fine chips. All impurities are washed and labels are dissolved. The clean shreds are then slowly dried and pigmented in an industrial oven. Finally, the plastic is melted at 280°C, extruded, and cut into polyester resins - the raw material used to create fabrics.
Because of its origin, rPET is often stigmatized as "toxic to wear". People and media argue that antimony and BPA contained in some water bottles can be cancerogenic and disrupt our endocrine system. Supposedly heat can cause these chemicals to be released and absorbed in our bodies from the skin. Experiments, however, show that this is unlikely to happen under the conditions of our everyday life. Just to be safe, it won't hurt keeping your clothes away from prolonged exposure to heat. For instance, don't leave them in your car when it's hot outside and skip tumble drying (unnecessary for 100% polyester anyway).
We shouldn't forget that various other chemicals are used in different stages of manufacturing - dyeing, finishing, etc. Probably the most reliable way to guarantee the safety of synthetic textiles is to look for products certified by OEKO-TEX 100 and Bluesign.
Is Recycled Polyester Eco-Friendly?
Let me start by stating the obvious; Achieving true sustainability is a long process, part of which is the continuous effort to create materials with lower impact.
We agree with the skeptics that rPET has its own caveats and certainly isn't an ultimate solution. At the same time it hard to deny that it reduces plastic waste, has a lower footprint compared to virgin polyester, and embodies the principles of circularity. We see it as a step in the evolution of material sourcing and a platform for future development.
Why choose rPET?
Why avoid rPET?
What is Bad About Recycled Polyester?
By now we have collected some good reasons why rPET may be preferable, but we can't ignore the fact that there is still a lot of room for improvement. The industry has to address a number of challenges before it can claim truly sustainable polyester production.
- Clothing-to-clothing recycling is still very uncommon. The mechanical method leads to lower quality plastic with every cycle, so clothes from rPET often end up in a landfill after first use.
- Recycling facilities also use non-renewable energy and water to run manufacturing. Utilizing green energy sources and recycling water is important to further reduce impact.
- Recycled polyester is usually more expensive than virgin; e.g. businesses don't have an economic incentive to invest in it.
- Chemical recycling will enable us to recycle plastics infinitely, but is even more expensive and comes with a higher environmental impact.
- Waste pickers in the developing world (1% of the urban population) earn approximately 5% of the source value. That's often below the living wage and insufficient to provide for their families. This creates a risk of children becoming involved in the informal supply chain.
- Recycled polyester is just as prone to shedding microfibers, so we have to make sure they don't escape our homes.
The conclusion is that "Recycled Polyester v2" will likely result from advancement in recycling technology, social and regulatory pressure to use low-impact materials, green industrial manufacturing, and social responsibility.