Material Guide: Synthetic Fibres & their Environmental Impact
Where does the raw material come from?
Conventional synthetics, which include most notably polyester, polyamide (aka nylon), acrylic and elastane, use raw materials derived from fossil fuels (oil, coal and natural gas) through chemical processes. They represent more than 68% of fibres used in the textile and apparel industry.
Recycled synthetics are produced from pre-consumer (i.e. off-cut fabrics from garment factories and excess plastic scraps from other industries) or post-consumer (i.e. rPET bottles, fishing nets) plastic waste. In most recent years, technology advancement has also enabled the commercialisation of bio-based synthetics made from renewable resources including fermented plant starch (from corn, sugarcane), castor oil and biomass (renewable organic material that comes from plants and animals). However, these still represent only <1% of the synthetics usedin the apparel industry.
What environmental impact does the material have?
A recent report published by McKinsey & GFA shows that around 70% of the fashion industry’s greenhouse gas emission come from upstream activities such as materials production, preparation & processing.
While synthetic fibre production has a lower environmental impact than natural fibres in terms of water consumption and wastewater, the energy required for production (125 MJ of energy per kilo of polyester produced) and the Greenhouse Gas emitted (14.2kg of CO2 per kilo of polyester produced) make conventional synthetics a highly energy intensive process. In 2015, the production for plastic based textile used more than 342 million barrels of oil, and polyester alone (80% of conventional synthetics produced) emitted 282 billion kg of CO2 – almost 3 times more than for cotton.
“In 2015, the production for plastic based textile used more than 342 million barrels of oil, and polyester alone (80% of conventional synthetics produced) emitted 282 billion kg of CO2 – almost 3 times more than for cotton”
GHG emission can be significantly reduced by switching to recycled synthetics, which use between 30-50% less energy to produce than virgin synthetics. However, one should be aware that recycled synthetics still rely on fossil fuel based material, and does not resolve other environmental issues associated with the non-biodegradable nature of the fibre (as discussed in the section “Micro-plastic Release”).
Bio-based synthetics are an emerging category of preferred fibre, providing good alternatives to the virgin and recycled counterparts due to their use of renewable resources and biodegradable nature. It is important to keep in mind that composting of bio-based synthetics requires proper industrial compost facilities to safely and efficiently process biopolymers through a biodegradable route.
As a petroleum-based material, virgin synthetic fibres do not biodegrade like natural fibres, instead it stays in the landfill for between 20 to 200 years. When washed, synthetic textiles shed microplastic fibres into waterways, which then enter into the ocean and are ingested by fishes and other aquatic creatures. This subsequently accumulate and concentrate toxins up the food chain, entering human bodies and the wider environment.
It has been estimated that between 0.8 and 2.5 million tonnes of primary microplastic released into the environment ends up in the ocean annually, and the washing of textiles accounts for 0.5 million tonnes of this (i.e. at least 25%). On the current track, there could be more plastics than fish in the ocean (by weight) by 2050. The presence of micro-plastic in the environment is a growing concern due to their negative impacts on the ecosystems and human health.
The issue of micro-plastic release should be tackled through:
- Changing the choice of materials used in garments to natural, bio-based or biodegradable fibres
- Technology innovation on washing machine (top loading washing machine sheds 5.3 times more)
- Using microfiber filters during the washing process (Rozalia Project and Guppy Friend are examples of start-ups developing these filters)
Factories producing synthetics without wastewater treatment systems can also release potentially dangerous substances such as antimony, cobalt, manganese salts, sodium bromide and titanium dioxide into the environment.
Each fabric category has its own advantages and disadvantages. For synthetics, they are more durable than most natural fibres and also offer versatile functions including light weight, waterproof, wrinkles and stains resistance, and quick to dry.
When choosing the right material for your product, our overall recommendations would be as follow:
- Use synthetics only when lower impact material cannot be used to achieve the desired function (i.e. technical or performance garments)
- Design your garments for longevity and encourage your consumer to take care of the garments according to the care label, to extend the useful of life
- Wherever possible, use bio-based or recycled alternatives to virgin synthetics
- Ensure the water treatment is well managed by choosing suppliers certified by Oeko-Tex and Bluesign
What else needs to be taken into consideration?
Limitation in recycling
There is a common misunderstanding that plastic can be recycled back into the same quality as its virgin state, but this isn’t the case. Each time polyester is melted down for recycling, it degrades and loses strength and quality. In essence, synthetic fibres cannot be recycled indefinitely and must be used for a lower quality purpose each time.
The ease with which synthetic can be blended with other fibres (i.e. fabrics with a blend of polyester and cotton) also causes problems with recycling. While mechanical recycling already offers a way to create textile from waste, it is based on a shredding process that generally results in lower value output process. In contrast, chemical recycling separate the constituent fibres and return them to virgin quality, offering the possibility for high-value recycling, however they are not yet technologically or economic mature to be applied on a commercial scale.
Relevant Standards & Certification
When sourcing recycled synthetics, the most relevant certifications to look for are Global Recycling Standard (GRS), Recycled Content Standards (RCS), Oeko-Tex 100 and Bluesign. GRS and RCS are standards for products with recycled content, providing brands a tool to verify that the product content is in fact from recycled material. Oeko-Tex 100 certifies raw, semi-finished and finished textile products and their production process at all processing level, to ensure safe chemical management and health standards are upheld during the production. Bluesign is focused on resource productivity, consumer safety, water and air emissions, using its Input Stream Management to ensure that unsustainable substances do not to enter the production cycle at all, but are eliminated from the start.
Where to get more info?
3. McKinsey & Global Fashion Agenda – “Fashion On Climate” report
6. Ellen MacArthur Foundation – “A New Textiles Economy: Redesigning Fashion’s Future” report