This article was extracted from the legends at Seventh Wave
So, can one neoprene be more green or eco-friendly than the other?
What contributes to limestone neoprene being more 'green' depends on its use of more sustainable and less toxic resources during production, and the longer its useful life span is (ie the longer it will stay out of landfill).
With this in mind, we explore the eco possibilities of the two kinds of neoprene below.
The core ingredient (97%) of limestone-based neoprene is calcium carbonate. Although a finite resource that needs diesel-powered equipment to mine it, there is an estimated reserve of limestone to last for 3,000 years. Arguably the extraction of limestone has less of an impact on the environment than oil-based neoprene, which depends on oil exploration, drilling, and potentially dangerous transportation (think oil spills). Also current oil reserves are fast being depleted. So despite both extraction methods being far from environmentally friendly, limestone would seem to be the more 'green' of the two.
Production of polychloroprene
Like oil-based neoprene, the production of limestone neoprene is an energy-intensive process, and needs heat to create the polychloroprene chips. However, Yamamoto, the main producer of limestone neoprene, argues that its production process uses one-tenth of the heat used in refining petroleum. This heat is made from burning used tires and using hydroelectric power sourced from several local dams, and any waste heat is then reused to power a local eel nursery.
The fact that limestone neoprene is considerably warmer due to its high micro-cell structure also means that less polychloroprene is needed in the production of a limestone-based wetsuit. In other words, 2mm limestone neoprene is as warm as a typical 3mm sheet of neoprene made from oil, which means there is less polychloroprene/raw materials needed and proportionally, less of an environmental impact.
The use of sustainable production techniques and components in the manufacturing of wetsuits is another way to lessen its impact on the environment. As pointed out by Patagonia, using recycled polyester or other kind of lining in the lamination process, as well as more environmentally friendly or nontoxic glues and adhesives would reduce a wetsuits environmental footprint. In other words, the whole manufacturing process needs to be refined in order to be really green.
Because of the durability of limestone neoprene, wetsuits made from it tend to last 2 to 3 times longer than wetsuits made from oil-based neoprene. Lasting suits reducing the ‘turnover’ rate of wetsuits, which means less wetsuits will end up as landfill if constructed from limestone neoprene, as opposed to oil-based neoprene. In this regard limestone is definitely more sustainable than other neoprene.
In conclusion, limestone neoprene is arguably more eco-friendly than petro-chemical neoprene, but there's a long way to go before a wetsuit and its production can be truly green. That's why Seventhwave, although proud to use limestone neoprene, has never tried to push its environmentally friendliness—we prefer green rooms than greenwash!