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Lego Challenge to find a Strong Sustainable Alternative Plastic

By 20th February 2020 June 30th, 2023 No Comments

Lego Takes On The Challenge To Find A Strong, Sustainable Alternative Plastic

You can build anything with Lego. All you need is a bit of imagination and some bricks in a range of shapes, sizes and colors. In this way, Lego bricks are a little like the atoms and molecules that chemists can create materials from. Since 1963, Lego blocks have been made of acrylonitrile butadiene styrene, or ABS. The hydrocarbon butadiene is derived from chemicals distilled from petroleum. Lego selected ABS as its material of choice for its structural strength and low chemical reactivity, its glossiness, its ability to incorporate vibrant color pigments evenly within the material, and its capability to be extruded and molded to create the interlocking shapes we know and love.

The robustness of ABS means that Lego bricks survive generations of play by both children and adults, with very little degradation or damage, even when you accidentally stand on them in the dark. While this indestructibility was one of the great selling points of plastics when they were first embraced as the future of manufacturing, we now better understand the issues that such persistent materials pose to our environment. It is for this reason that Lego, like many other manufacturers, is looking to fossil-free alternatives that are less polluting to the environment.

By researching plant-based plastics, Lego had hoped to join the likes Vegware, with its compostable alternatives to plastic cutlery and food containers. However, the quest to replace fossil-fuel based plastics with plant-based alternatives that have a less harmful impact on the environment is a tough one, especially as Lego hopes to find a plant-based alternative that will not degrade over time, but will last for many generations of play.

Lego researchers are struggling to find a material that possesses as many of the versatile properties that ABS has. Since 2012, over 200 potential alternative materials have been created, but few have lived up to Lego’s high standards of quality. As a result, just 2% of products since then have been made from plant-based plastics. Somewhat delightfully, plastics made from Brazilian sugar cane have been used to create trees and leaves, notably in the Lego Treehouse set, which holds the accolade of having more sustainable bricks than any other set. The leaves of the treehouse can afford to be more flexible as they are structurally less vital.

The company attempted to create bricks from corn-derived plastic, but these were far too soft to build with, and assembled sets ran the risk of bending and sagging over time. Wheat-based plastics had difficulty evenly distributing color pigments through the material which gave an uneven color, and they were also deemed to be too dull compared to the bright, glossy appearance of a regular brick.

Lego’s stated commitment to sustainability includes using more recycled products, but also the discovery and implementation of sustainable alternatives to fossil-fuel derived plastics by 2030, but with just a decade left to action to do this, it’s followed the example of some of the most groundbreaking science to achieve its goal.

In particular, Lego is following the example of CERN, which is a collaboration of hundreds of scientists around the world, having invested about $150 million in the establishment of a Sustainable Materials Center at it Danish headquarters in Billund. The center will be looking into finding sustainable alternatives for both bricks and packaging. Researchers at the Sustainable Materials Center will also be working with companies and institutions that are experts in developing materials that have a less negative impact on the environment.

In 2018, Lego filed a patent for a biopolymeric material and its manufacturing method. The patent was published in June and details the fascinating characterization tests that these materials must undergo once they have been molded into bricks. The assembly and disassembly test scores the bricks on their ease of being joined together and being pulled apart by ‘an average human’ (whatever that may scientifically mean), while the drop test looks at how well the bricks survive a weight being dropped on top of them. The height of the drop is increased by 2cm in each round, until the bricks finally show signs of damage. Testing to this level of destruction shows how robust these materials must be to pass Lego’s quality standards. A classic Charpy impact test is also used to determine the material’s energy absorption on impact, though traditionally sized notched rods of the biopolymer material are used in this test.

While developments such as this are encouraging, the robust nature of the bricks does mean that if they are disposed of, they will eventually contribute to the global microplastics problem as they cannot easily degrade. Lego doesn’t accept bricks for recycling, instead encouraging people to gift them to others. Furthermore, care must be taken to ensure that whatever alternative materials are selected and implemented in the manufacturing of Lego bricks in the future, their environmental impact doesn’t exceed that of current bricks.

By working with a range of stakeholders, including environmental charities like the World Wide Fund For Nature, organizations like the Bioplastic Feedstock Alliance, and other materials science experts, fossil fuel-free Lego bricks could well be a reality within the next decade.

Unfortunately, thanks to the company’s standards, they will probably still hurt just as much when you step on them in the dark.


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