Walking on eggshells tends to bring stress and strife, but is it possible that driving on them could be a breath of fresh air? That’s the idea behind a patent submitted by Stellantis that takes eggshells out of the compost bin and puts them into the tire compound.
The patent idea is simple: extract calcium oxide (CaO) from discarded eggshells and use the material to replace carbon black and silica as a tire filler and coupling agent. Stellantis actually filed its paperwork with the United States Patent and Trademark Office back in mid-2023, but the U.S. Patent and Trademark Office didn’t publish the filing until last month. The January 23 notice was unearthed by CarMoses.
But why bother? The reasons are many. Eggshells are a naturally-recurring material that can be sourced anywhere. Stellantis writes that hen eggs, for example, are more than 90% calcium carbonate, from which the calcium oxide can be gathered. Removing shells from landfills reduces waste, and using bio-waste to replace chemical-derived materials means less poison for the environment and our insides.
Oh, and yeah, as CarMoses points out, calcium oxide can improve a tire’s rolling resistance and enhance grip in wet conditions. Stellantis says its CaO-infused tire formula will improve fuel efficiency by about 3% and rolling resistance by 20% when compared to a standard tire made with carbon black.
Stellantis isn’t trying to get rid of tires. What’s a car to do without them? But to humans and every living thing that requires oxygen, tires are more like a necessary evil. Natural rubber is milky white and comes from trees. Trees, of course, purify the air, provide shade, a friend to lean on, etcetera. Rubber tires, on the other hand, are produced using natural and synthetic materials. But that artificial stuff is not good; on the contrary, it’s horribly unhealthy.
For example, tires are not white because of the carbon black pigment that’s added. Stabilization of chemicals within the tire compound, sun protection, and heat dispersion are among the benefits of carbon black. However, it’s derived from soot, which isn’t something you’d want to sprinkle on your food.
Studies claim tire degradation creates more pollution than exhaust fumes, and additional research has shown that most of the microplastics floating in the ocean and waterways—the bits that can’t break down ever—are tire particles. So, we’re directly and indirectly breathing, drinking, and ingesting old tires. Tasty.
But I’m not into that kind of Flavortown. I have no desire to order a slab of rubber as my next meal. Is it a shot in the dark, though? Stellantis explains some of the extraction process, including having to expose the eggshells to high temperatures of at least 900°C. This will decompose the eggs into literal dust (calcium oxide), which then undergoes milling. Beyond that, further details such as how the CaO will be added to the tire compound, info regarding overall manufacturing processes (e.g., costs, time), or whether the eggshell tires would even remain black were not disclosed.
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