The fashion industry is getting more and more involved in sustainability. One of the upcoming novelties is recycled polyester, also known as rPET. But how sustainable is this really?
Recycled polyester, also known as rPET, is a textile made from recycled plastic bottles. It is an alternative to traditional polyester, as that is far from being a sustainable textile. Even though it is not particularly environmentally friendly, it is still one of the most used materials in clothing. The reason for that is that there’s a lot of demand for it, because of the resistance and stretchiness of the garments.
Why is virgin polyester not sustainable?
Polyester is made from polyethylene terephthalate (PET), which is the most common type of plastic in the world. Therefore, polyester is a derivative of petroleum, which is a fossil fuel. It was invented in 1941 by British chemists and boomed in the 70s when it was advertised as “a miracle fiber that can be worn for 68 days straight without ironing, and still look presentable”.
As previously mentioned, this textile is resistant and stretchy. On top of that, it is durable, easily dyed, easy to look after, and quick-drying. It is, therefore, not a big surprise that the fashion industry often opts for polyester as a material.
In terms of land and water use, polyester has a lower impact than natural fiber production. However, it is a high-impact process as the production uses a lot of energy. Besides that, it also doesn’t perform well when looking at pollution. Potentially harmful substances, such as antimony and cobalt, could get released into the environment without a proper wastewater treatment system. Polyester also does not biodegrade, as it is an oil-based plastic. This leads to it staying in landfills for a very long time. Also during its lifetime, it causes pollution. When polyester garments are washed, they release microplastics.
Why is recycled polyester a good alternative?
Instead of using crude oil to make polyester, recycled polyester uses plastic bottles (PET-bottles). There are multiple reasons why that is a good alternative:
1. It diverts bottles from landfills
This is obviously a good thing as PET bottles that used to go to landfills, now end up getting used again. However, it is slightly more intricate than that.
rPET is divided into two different sorts: post-consumer and post-industrial. Post-consumer PET comes from bottles, whereas post-industrial PET comes from byproducts of manufacturing. For this reason, post-consumer PET is seen as the “greenest” option.
2. rPET production uses less energy
Research has shown that it takes 33% to 53% less energy to produce recycled polyester than it takes to produce virgin polyester. Where virgin polyester uses approximately 125MJ per KG of fiber, recycled polyester would take between 59MJ and 84MJ per KG of fiber.
Why is it harmful?
As explained above, post-consumer PET is favourable, which explains the surge in demand for used bottles. Since demand is surpassing supply in some areas, certain suppliers are buying new bottles to use in the manufacturing of rPET. This way, they can still call their product a ‘recycled’ fibre. For this reason, you can never be 100% sure that the recycled polyester garment you’re buying is truly made of recycled polyester.
2. Only human labour preps the bottles
Post-consumer PET is favourable when it comes to the product’s life cycle. However, the bottles used by consumers have to be cleaned. Most of those bottles come with a label, which has to be removed before getting turned into the polyester. This is almost always done in low-income countries, which is socially not responsible. On top of that, these bottles have to get transported to those countries from all over the world, which results in its own set of environmental question marks.
3. Release of microplastics
Recycled polyester still releases microplastics when washed. Plymouth University recently did a study on the effects of running a load of wash. They found that one cycle can release more than 700,000 plastic fibres into the environment.
4. End of their life cycle
When transforming used PET bottles into polyester garments, we’re basically ending their life cycle. Fabrics are backed, laminated, or finished chemically. They could also get blended with other synthetic materials. Both of these lead to them not being able to get recycled mechanically. Chemical recycling could separate out the various chemicals, but it is a very expensive process and therefore not often used. There are more and more manufacturers currently working on accelerating the adoption of more sustainable ways. Hopefully one day, we can have synthetic fibres that are not only recycled, but also recyclable.
What's the verdict?
Even though recycled polyester is one step in the right direction, it is still not as sustainable as we’d like it to be. Many studies are still being conducted on not only the exact numbers when it comes to sustainability but also on how to make the process more sustainable. The most sustainable option when you need new clothes is to buy them second-hand. However, when the occasion arrives you have to buy something new, choosing recycled polyester instead of virgin polyester is already a good start!