The Smart Sustainable Plastic Packaging Challenge Fund (SSPP) was established to support investment in research and innovation in plastic packaging to help the UK achieve the very stretching Plastic Pact targets. And it’s one of these targets - that, by 2025, all plastic packaging should contain an average of 30% recycled content. When discussing this target I very often hear the question being asked “so how many times can plastic be recycled then?” usually after a bold statement about the infinite recyclability of other materials. This would be a really interesting question if recycling was organised that way, but the problem is that it just isn’t.
We don’t gather all the plastic bottles that have been made with 100% virgin plastic, make sure they are all recycled together, then, after those are used, gather all these “first time round the loopers” and make sure these all go round together in an exclusive group. This would be incredibly difficult to achieve and counterproductive anyway. In real world recycling, material does flow in a loop but this loop has new, virgin material added - and at the same has some material removed.
From the above diagram we can conclude that, rather than considering how many times plastic can be recycled, we ought to be looking at the age distribution of the polymer circulating in a specific recycling system.
Still not convinced? Imagine you are holding a handful of recycled plastic pellets. Now ask yourself how many times have these been “round the loop”. Too difficult?
So take just one pellet and ask yourself the same question... It is still unanswerable.
The truth is that even that one pellet will be a mixture of plastic that has been round once, twice, some of it even ten times or more. This is why we must instead start to consider the age distribution of the plastic in a recycling loop. Helpfully, to at least a first approximation, the steady state age distribution of plastic circulating in a recycling system does not vary with time and is determined by only two factors:
% of articles in a system with recycled content
% average recyclate content