Scallops' soft bodies are well-protected by their hard shells, so … could those same shells protect human heads? That question was asked by the Japanese designers of the Shellmet, which is a helmet made partially of scallop shells.
The Shellmet is the result of a partnership between Koushi Chemical Industry and Sarufutsu Village, the latter of which is a fishing community that generates approximately 40,000 tons (36,287 tonnes) of waste scallop shells every year. Although there are some potential uses for that waste, most of the shells reportedly end up just sitting around in smelly heaps for long periods of time.
Utilizing a process developed by Prof. Hiroshi Uyama from Osaka University, the shells are first boiled and sterilized, then pulverized and rendered into calcium carbonate powder, which is mixed with powdered discarded plastic and rendered into pellets. Those "Shellstic" bioplastic pellets are subsequently poured into a helmet mold and heated, causing them to melt.
Once the bioplastic has cooled and hardened, the result is a helmet with a scallop-shell-inspired ribbed design. That design, along with the inclusion of the calcium carbonate, is claimed to make the helmet about 33% stronger than it would be otherwise. Additionally, the production process is said to generate approximately 36% fewer greenhouse gas emissions than if 100% virgin plastic were used.
The Shellmet is intended mainly for use by fisheries workers – a trial of that application is planned to begin this spring (Northern Hemisphere). The helmet may also be offered for use in disaster scenarios, or other situations in which hard hats are required.
Safety standard certification is currently in the works. That said, the Shellmet is already available for preorder, in a choice of five colors. It is priced at 4,800 yen (about US$36).
There's more information in the video below.
Source: Koushi Chemical Industry
Is there any other benefit from using this discarded bioplastic? If the helmet is intended for a short lifespan, it's probably non-recyclable. It can't even be used as fuel, due to the high mineral content. They didn't say that it was highly biodegradable.
It sounds like an attempt to scam some green funding. Dumping the shells in the ocean will at least buffer some acidity caused by high CO2 levels. They probably form a good habitat for some ocean organisms. Binding the shells into open structures (robots cementing them with mineral cement?) would benefit even more species, but that's the opposite of having people pay for the unwanted shells.