Green Bean

Castor oil replaces petroleum in plastics, from ski boots to shades.

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Remember castor oil? It’s that thick, gooey oil your grandmother spooned down your throat to cure what ailed you. She was onto something, since castor oil has real medicinal properties (it contains ricinoleic acid, which acts as an an anti-inflammatory when it penetrates the skin). But new uses are being discovered for castor oil — namely, as a substitute for petroleum in plastic.

At the most recent Outdoor Retailer show, castor-oil-based plastics were popping up in everything from ski boots to sunglasses. Last January, Scarpa North America announced that it had taken three of its most popular AT and telemark boots and built them with a castor-oil-based Pebax that has all the same characteristics as petroleum based Pebax—except that it’s better for boots because it retains its stiffness in a wider temperature range. And because when all is said and done, it uses 29 percent less fossil fuel and puts 32 percent less emissions into the environment.

This summer, Smith Sport Optics followed suit with a new line of sunglasses that will hit the market in January. Smith’s “Evolve” collection uses a castor-oil-based plastic resin that’s comfy on the face, light, impact-resistant, durable and flexible. The glasses use 54 percent castor-oil-based raw material.

We don’t know if castor oil has any of the same issues of corn-based plastics, which have been controversial in some applications because while they do reduce the amount of petroleum in the final product, they use significant petroleum inputs throughout the production of the corn itself. We’re looking into it, and will report back!

In the mean time, you can get more info from the folks who make these plastics, Arkema, or from the Scarpa website. The Smith collection is so new, it’s not yet on their website.

—Berne Broudy