Let's see all the PROS of using recycled polyester
It keeps plastic bottles from going to landfills
Recycled polyester gives a new life to plastic bottles, which are not biodegradable and would otherwise stay in landfill for centuries. Estimates have shown that approximately 5 to 13 million metric tons of plastic end up in the oceans annually. Using old PET bottles to produce recycled polyester fabrics extends their lifecycle.
It has a lower impact than virgin PET
It has been shown that manufacturing rPET requires around 60% less energy and emits up to 32% less CO2 in comparison to production of virgin polyester.
It reduces the use of crude oil
By using recycled polyester, we can drastically reduce the extraction of crude oil.
Let's see all the CONS of using recycled polyester
It does NOT help fashion circular economy of polyester garments
Recycled polyester garments are often made from recycled PET bottles, not from old polyester garments. So, it means that there are still a lot of non-biodegradable polyester garments in landfills around the world. And this is a lot if you consider that polyester accounts for 52% of the fibres used in the textile and apparel industry.
It's weaker than virgin polyester (If created mechanically)
Most rPET is mostly obtained through mechanical recycling, as it is the cheapest process available on a large scale. However, through this process, the fibre loses its strength and thus often needs to be mixed with virgin fibre.
It's not recyclable again
Most people believe that plastics can be infinitely recycled, but each time plastic is mechanically taken back to chips and heated, it degenerates, so it cannot be recycled a second time, due to a steep decline in its quality. "So it is not really circular, it's only a delay to landfills" as said by VIRTUE+VICE
It's still not really energy-efficient compared to natural fibers
Even though rPET takes 59% less energy to be produced than virgin polyester, it still requires more energy than hemp, wool and both organic and regular cotton, according to a 2010 report from the Stockholm Environment Institute. This is why fashion brands are more and more encouraged to favor natural fibers as much as possible, even because their recycling processes are mechanical and extremely low-impact.
It's still chemically dangerous
Another issue concerning the recycling process of polyester is that the chips generated by mechanical recycling can vary in color, making color consistency difficult to achieve. This is why, most of the time, chlorine-based bleaches to whiten the base are used, and this also requires large amount of water, energy and chemicals.
It releases microplastics
Polyester - either virgin or recycled - generates plastic microplastics during each wash, which are released in the wastewater and then into the oceans.
It releases more Antimony than virgin polyester
Some recent studies have shown that PET bottles leach antimony, a substance that is known to be cancer causing. Antimony oxide is typically used as a catalyst in the process of making PET bottles and polyester. Textile Exchange notes that whilst the concentration of antimony is rarely high enough in rPET clothes to affect us, finding substitutions to these chemicals will be important in the long run.