Updated: Jul 11, 2022
An insight into polyester
Polyester is the most widely used fibre in the world; you will find polyester on an array of garment labels, from chunky knit jumpers to silky dresses and part of most soft furnishings. According to the Textile Exchange, it accounts for roughly half of the overall fibre market and around 80% of synthetic fibres.
Polyester is a generalised term for any fabric or textile made using polyester yarns or fibres. It is a shortened name for a synthetic artificial polymer, which is most commonly referred to as a type called polyethene terephthalate (PET). PET is most recognisable as plastic bottles.
British chemists John Rex Whinfield and James Tennant Dickson created polyester in 1941.
They had built on DuPont laboratories work in America, which began experimenting with polymers, creating nylon, neoprene and artificial silks in the 1930s.
Polyester is usually derived from crude oil petroleum. It is processed through a system called 'cracking', which treats the petroleum through an intensive method to break down the molecular structure.
Once polymerised, PET is created in a liquid form. This liquid can then be extruded, dried and chopped into small pellets and is ready to be spun through industrial spinnerets. Once cooled and hardened, it forms a polyester yarn that can be woven into a textile.
Why Use Polyester?
Polyester is a versatile material, and like many inventions, it was considered a remarkable breakthrough and the perfect solution. Within 20 years, various mills and companies had developed their own version. As polyester production is low cost and can be manufactured quickly, its popularity has grown alongside that of fast fashion.
Polyester's benefits include; its ease of washing with stain and wrinkle-resistant properties and a quick drying time. Polyester blends well with other fibres, like cotton and wool, to create a durable material, which is why it is often used in hardwearing garments. It also takes and holds dye better than natural fibres. Polyester requires a high-temperature dying process, but it requires fewer chemicals and time than fibres like cotton, making the overall environmental impact lower.
Polyester is often considered more sustainable from a consumer care standpoint because it requires less water, energy and heat for washing. Polyester garments last a very long time, making them perfect for uniforms and technical garments because their longevity reduces consumption and waste. Ecotextiles points out that "[polyester] 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?"
The Issues with Polyester
Polyester is usually derived from petroleum, also known as crude oil, a fossil fuel that is natural non-renewable and non-biodegradable. We are currently using petroleum faster than it can be produced by nature. Producing plastic-based fibres for textiles uses an estimated 342 million barrels of oil every year, according to A New Textiles Economy Report 2017.
The supply chain for polyester is not transparent. Petroleum is one of the most challenging raw materials to trace back to the source, bear in mind that the top sources of crude oil are (in order): Saudi Arabia, Russia, the U.S., China, Iraq, Iran, and Canada. Polyester can be considered a conflict material; as its primary ingredient, oil is a leading cause of war. Between one-quarter and one-half of interstate wars since 1973 have been linked to oil.
The process of converting crude oil to fabric requires high amounts of energy.According to the Common Objective, the energy required to produce polyester (125 MJ of energy per kilogram produced) and the greenhouse gas emitted (14.2 kg of CO2 per kilogram produced) makes it a high-impact process. In 2015, polyester produced for clothing emitted 282 billion kg of CO2 – nearly three times more than for cotton.
Recent studies have shown that polyester sheds tiny pieces of plastic called micro-plastics with every wash over time. These fibres are in our ecosystems, ingested by marine life, animals and even us. It has been estimated that around half a million tons of plastic micro-fibres are shed into the oceans annually while washing plastic-based textiles such as polyester, nylon, or acrylic. The full extent of micro-plastic impact is still being investigated but is it a huge global issue that could have detrimental impacts.
Recycled polyester - rPET
Polyester has a significant adverse environmental impact during production, use and disposal. Recycled polyester is an excellent solution to keep the material's benefits but reduce the carbon footprint. There are two ways of doing this; chemically and mechanically recycled polyester.
The first comes from clear PET plastic bottles, which are cleaned and shredded to go through a de-polymerisation and re-polymerisation process to be turned into PET chips. These PET chips or pellets can be used to make clothing, insulation, new water bottles, and much more. For polyester, yarns are melted and spun onto reels. It is estimated that in 2016 2.9 billion plastic bottles were diverted from landfills to be recycled into polyester yarns.
Polyester was one of the first fashion fibres to be recycled into a brand new fibre and the most common to see brands use. For example, Econyl and rPET are often used for swimwear.
The other method is to use textile waste as a raw material resource, diverting it from landfill and incineration. Used clothes and garment production waste is cleaned and processed before shredded; these fibres are primarily used in carpets, bedding, and other textile applications.
Performance, durability and high strength of rPET are the same as virgin polyester but with lower environmental impact; for future use, it should be the only choice for polyester.
Certifications to look out for when buying polyester -
- Recycled Claim Standard (RCS)| The Textile Exchange RCS
Textile Exchange Preferred Fiber Materials Report 2017
Written by Bethan @ theecostories