Here, we list some points to discuss about this issue.
1. Energy needed to make the rPET is less than what was needed to make the virgin polyester in the first place, so we save energy.
It is true that recycling polyester uses less energy that what’s needed to produce virgin polyester. Various studies all agree that it takes from 33% to 53% less energy. rPET is also cited as producing far fewer CO2 emission than does the production of virgin polyester around 54.6%.
2. We’re keeping bottles and other plastics out of the landfills.
But the game gets a bit more complicated here because rPET is divided into “post consumer” PET and “post industrial” rPET: post consumer means it comes from bottles; post industrial might be the unused packaging in a manufacturing plant, or other byproducts of manufacturing. The “greenest” option has been touted to be the post consumer PET, and that has driven up demand for used bottles. Indeed, the demand for used bottles, from which recycled polyester fiber is made, is now outstripping supply in some areas and certain cynical suppliers are now buying NEW, unused bottles directly from bottle producing companies to make polyester textile fiber that also can be called recycled.
3. Recycling has its limitations.
There are two ways to recycle PET: mechanically and chemically. “Mechanical recycling is taking a plastic bottle, washing it, shredding it and then turning it back into a polyester chip, which then goes through the traditional fiber making process. Chemical recycling is taking a waste plastic product and returning it to its original monomers, which are indistinguishable from virgin polyester. Most rPET is obtained through mechanical recycling, as it is the cheapest of the two processes and requires no chemicals other than the detergents needed to clean the input materials. However, “through this process, the fiber may lose its strength and thus needs to be mixed with virgin fiber”.
4. The process of recycling PET impacts the environment, too
The recycling process of polyester is that the chips generated by mechanical recycling can vary in color: some turn out crispy white, while others are creamy yellow, making color consistency difficult to achieve. Some dyers find it hard to get a white, so they’re using chlorine-based bleaches to whiten the base. Inconsistency of dye uptake makes it hard to get good batch-to-batch color consistency and this can lead to high levels of re-dyeing, which requires high water, energy and chemical use.” Moreover, some studies suggest that PET bottles leach antimony, a substance “known to be cancer causing”.
5. Recycled polyester releases microplastics
Man-made fabrics can release microscopic plastic fibers -- the infamous microplastics, and each cycle of a washing machine can release more than 700,000 plastic fibers into the environment. It doesn’t matter if garments are from virgin or recycled polyester, they both contribute to microplastics pollution.
There are many articles discussing related these issues, and each has its own supporters. If we exclude brands’ marketing factor, recycled polyester as a whole still can reduce the damage to the environment. Nowadays, our technology and cost still can’t make the recycled polyester to be 100% decomposed, but it can extend the usability of PET, and also reduce the demand of the petroleum and energy consumption. In addition, polyester is still more suitable for outdoor sports due to its physical characteristics. Therefore, in order to achieve the functionality of clothes while reducing the damage to the environment, recycle polyester was born.
Source: www.oecotextiles.wordpress.com, www.fashionunited.uk