The brick must also not only retain its shape and retain that clutch, but throughout generations of play, as Brooks says such materials retract and change shape over time. Standard Lego bricks are tested at high and low temperatures, butter, and even fake saliva to ensure they maintain their integrity over decades of use.
However, with his new PET brick, Lego broke it. Well almost. “We need to work now on how to lightly tighten the clutch and how to add brick colors,” Brooks says. “Once we do that, we’ll go through shape by shape and determine how many ABS bricks can replace PET.”
The key here, of the 3,500 or more different shapes that Lego produces, the 2 x 4 brick is one of the most popular. If the company can replace such a component with a recycled plastic version, it will have a significant impact on Lego’s environmental goal of using fully sustainable materials in its products by 2030. “We have what we call ‘runners,'” Brooks said. For example, we know that most sets will have 2 x 4, we certainly know quite a bit each the set will have 1 x 1 point. It is by far the most common brick we make. “
“ABS is incredibly rigid. Very rigid, very precise, very hard. PET is less rigid, less hard and less precise, so we need to use a PET impact modifier. That is what is different here. We use a different class of PET with the added ‘secret sauce’ for which we have a patent. So, you are looking at a PET that we are modifying to behave like ABS. “
Gregg Beckham of the National Renewable Energy Laboratory of the U.S. Department of Energy, who in 2018, along with John McGeehan of the University of Portsmouth, created an enzyme that digests PET, is impressed with Lego’s progress.
“ABS is an amazing material. It is extremely versatile, as you can change the ratio of A, B and S. And depending on how you formulate it, there are a very large number of versions of ABS plastic that you can make. We literally touch it every day, ”says Beckham. “PET, on the other hand, is a challenge to formulate in a way that has the same material properties as ABS as you would find in Lego bricks. This is certainly an extraordinary challenge in polymer science. This is super exciting. ”
As for why it took so many decades of plastic production to get to this point, Beckham says that while it would be nice if we could wave a magic wand and just accomplish it, in many cases the task is deceptively difficult. “This is a fundamental science of material and engineering that must discover how to fulfill the same types of material properties with raw materials that are either recycled plastic or can be recycled themselves,” he says. “In the case of ABS bricks, they are not made of recycled plastic nor are they recycled at the end of their life. This could simultaneously address both of these challenges. “
There is another benefit of the new PET brick prototype: it has a 70 percent reduction in carbon compared to a base brick made of ABS material.
But interestingly, while the development of new ecological plastics is underway, the real environmental benefits may come from developing ways to recycle things we can’t at the moment. Things like ABS. “Laboratory research today is considering using advanced recycling approaches that are able to break down polymers, and long chains of molecules, into their building blocks,” Beckham says. “Then purify them and turn them back into the same plastic that had the same virgin quality of plastic, or recycle them and turn them into something else that’s even more valuable.”