When we talk about recycling plastics, most of us envisage ‘mechanical recycling’. This refers to operations that recover plastics via mechanical processes, usually involving the collection, sorting, washing, shredding, identification and separation, and, finally, extruding and compounding of plastics.
The finished materials may be converted into products that offer a substitute for environmentally-harmful virgin products.
Mechanical recycling – also known as material recycling, material recovery or back-to-plastics recycling – is currently the almost sole form of recycling in Europe, representing more than 99% of recycled quantities, according to the industry association Plastics Europe.
However, there are limitations to this commonly-used method.
Martin Stephan is Deputy CEO at enzymatic processes specialist Carbios; he tells Cosmetics Business: “Mechanical recycling of plastics is not so much ‘recycling’ as a ‘reuse’ process. It’s good, but it's not sufficient. For example, to be able to have products which are suitable to make a transparent bottle, you need, as an input, transparent bottles.
“And then this process can be done five or six times, but not more, because after five or six cycles, the polymer is so damaged that you cannot use it to make a bottle any more. So it will end up in the environment, or incinerated, or as landfill. That's why I say it’s not fully ‘recycling’.”
Additionally, Stephan notes: “You cannot mechanically recycle mixed plastic, since they grind and melt everything together. So if you have PET [polyethylene terephthalate] mixed with other polymers, like polyethylene or polystyrene, which can happen, this cannot be recycled. They need pure PET to recycle, called pure polyethylene or pure polypropylene.”
However, increasingly beauty brand owners and cosmetic packaging manufacturers are making headlines by teaming up with innovators offering plastics created via non-mechanical forms of recycling.