Updated: Aug 20, 2020
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. It accounts for roughly half of the overall fibre market and around 80% of synthetic fibres, according to the Textile Exchange.
Polyester is a generalised term for any fabric or textile, which is made using polyester yarns or fibres. It is a shortened name for a synthetic man-made polymer, which most commonly refers to as a type called polyethylene 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, who 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 though an intensive method to break down the molecular structure.
Once polymerized PET is created in a liquid form. This liquid can then be extruded, dried and chopped into small pellets and is ready to be melt spun through industrial spinnerets. Once cooled and hardened, it forms a polyester yarn that can then be woven into a textile.
Why Use Polyester?
Polyester is a versatile material and like many inventionsit was considered a wonderful breakthrough and the perfect solution. Within 20 years various mills and companies had developed their own version. As the production of polyester is low cost and can be manufactured quickly, its popularity has grown alongside that of fast fashion.
A few of the benefits of polyester 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 fibers. Polyester requires a high temperature dying process, but it requires less chemical and time than for fibres like cotton, making the overall environmental impact lower.
Polyester has often been 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, which makes it perfect for uniforms and technical garments because its longevity reduces consumption and waste. As Ecotextiles points out: “[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 which is also known as crude oil, a fossil fuel that is a natural non-renewable resource and non-biodegradable. We are currently using petroleum faster than it can be produced by nature. Producing plastic-based fibers 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 difficult raw materials to trace back to the source, bare 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 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.
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) 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.
Recent studies have shown that over time polyester sheds tiny pieces of plastic called micro-plastics with every wash. These fibres are in our ecosystems, being ingested by marine life, animals and even us. It has been estimated that around half a million tons of plastic micro-fibers are shed into the oceans annually during the washing of plastic-based textiles such as polyester, nylon, or acrylic. The full extent of the impact of micro-plastic is still being investigated, but is it a huge global issue that could have detrimental impacts.
Recycled Polyester - rPET
Polyester has a significant negative environmental impact during production, use and disposal. Recycled polyester is good a solution, to keep the benefits of the material but reduces the carbon footprint. Their 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 then 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 they are melted and spun on to reels. It is estimated that in 2016 2.9 billion plastic bottles were diverted from landfills to be recycled back into polyester yarns.
Polyester was one of the first fashion fibers 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 being shredded down; these fibres are largely used in carpets, bedding, and other textile applications.
Performance, durability and high strength of rPET is 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