Every year, the world produces over 380 million tons of plastic. Lego alone accounts for about 100,000 tons each year, just to create toys for children (and in many cases, for their fathers as well). While the figure of 100,000 seems small compared to the total 380,000,000 tons, it is enough plastic for Lego to produce 110 billion toy bricks.
Most Lego pieces are made from ABS plastic.
What is most concerning is that the vast majority of those 110 billion plastic bricks are made from a material called acrylonitrile-butadiene-styrene, abbreviated as ABS. This material is derived from petroleum and is one of the most popular plastics due to its durability after thermal processing. The issue is that when recycling ABS plastic, its durability decreases with each subsequent use, and because of its durability, it takes over 1,000 years for ABS plastic to fully decompose in the natural environment.
This is also why, in 2015, after 66 continuous years of producing beloved plastic brick toys for millions of children worldwide, with non-recyclable pieces, Lego announced an investment of $155 million from their massive $7 billion revenue fund to open a Sustainable Materials Center.
The first product from this center is a material made from sugarcane-based synthetic plastic. This material took Lego scientists two years to perfect the polyethylene structure formula. However, it is not as durable as traditional ABS plastic bricks, so it is only used for decorative elements like trees or leaves. The sugarcane-based plastic bricks from Lego account for only 2% of the total plastic toy bricks they produce annually, as seen in the tree detail set below:
The tree detail set is made from sugarcane-based synthetic plastic.
However, the Sustainable Materials Center has recently introduced the classic 2×4 brick, a staple for Lego enthusiasts, and instead of using sugarcane-based bioplastic, Lego has found a way to recycle PET plastic bottles to create toys for children. This marks the first time Lego has produced a recycled plastic brick that meets almost all durability requirements of traditional ABS bricks.
To achieve this, over the past three years, a team of 150 engineers at the Sustainable Materials Center has experimented with more than 250 different types of PET plastic. The result, as you can see in the image above, is a brick that meets Lego’s standards for grip. This concept describes the ability of two Lego bricks, whether produced in 1980 or 2020, to fit together snugly. If a plastic piece is not durable enough or shrinks excessively during production, it will not fit together effectively.
With the new recycled PET material, Lego is close to meeting all their requirements.
Tim Brooks from Lego stated: “We accept a plastic brick size variance of 1 to 2 microns, smaller than the thickness of a human hair. This number is incredibly precise considering consumer product standards. Therefore, grip is the biggest challenge we face. If the variance is too large, either the test plastic piece will not assemble as desired, being either too loose or too tight. Molding such a plastic piece is very difficult. The plastic material will be pressed like toothpaste into a mold at high temperatures, then cooled to form the brick. At that point, the material will shrink, and you don’t want it to shrink too much.”
Molding a plastic piece to the correct specifications is challenging, but keeping it durable across generations is even harder. Standard Lego bricks are tested for durability at high and low temperatures, lubricated, and even subjected to artificial saliva to ensure they can last for decades without deforming. With the new recycled PET material, Lego is close to meeting almost all their requirements, including the grip between bricks. Now, Lego’s challenge is to optimize the grip of recycled plastic bricks, add colors to each brick, and then select which brick designs will have the most positive impact if they switch from ABS to recycled PET.
Lego’s challenge now is to optimize the grip of recycled plastic bricks.
Among the more than 3,500 different Lego plastic bricks, the 2×4 brick is the most popular. If all the 2×4 bricks in millions of Lego sets sold on the market were changed to recycled plastic, the environmental impact would be significant, while also supporting the goal that by 2030, Lego toys will only use sustainable materials. Next in line will be the tiny 1×1 bricks, which are present in almost every Lego set.
Mr. Brooks said: “ABS is very tough, very precise, and very durable. Meanwhile, PET is inferior in every aspect, so we need to apply customized solutions for the plastic structure. That’s the fundamental difference. We use PET plastic structures different from a secret additive that is patented, to create plastic bricks that have the same durability as ABS.”
Gregg Beckham, an expert from the National Renewable Energy Laboratory of the U.S. Department of Energy, who in 2018 created an enzyme to break down PET plastic, expressed his admiration for Lego’s achievements:
“ABS is a miraculous material. It is extremely versatile because you can customize the content and proportions of each component A, B, or S. Thanks to this adjustability, there are many different types of ABS plastic that we touch and use every day. In contrast, PET is very difficult to produce a sustainable structure like ABS, which Lego bricks are famously known for. This is a special challenge in the field of polymer science, and its results are truly impressive.”
Lego’s future goal is not only to find alternative materials to replace ABS but also to develop methods for recycling PET plastic and eventually ABS plastic efficiently.
