Biocouro is the trade name of a wet-white based leather (technically metal-free) with a wet-end process specially developed to improve its biodegradability. Biocouro products are non-allergenic and contribute to the prevention of cutaneous diseases that often appear in the feet. Therefore, these products are suitable for use in footwear, in particular for lining or upper, when the shoe does not have lining. Curtumes Aveneda is one of the tanneries in the world with more history in wet white production. The path of ecological leather production began in 1988 with the first wet-white batch, at the time in Curtumes Miguel Branco (company associated of the Curtumes Aveneda, Ida.). Through all these years, the tanning and wet-end processes have evoluted, and recently all the process has been developed to improve the biodegradability of the product. This evolution changes the concept of Biocouro, turning it more sustainable.
A normal wet-white production is more eco-friendly than chromium based tanning.
Because generates tanned solid wastes with more possibilities of material valorization. Biocouro, developed in Curtumes Aveneda, is more than that. In this case, the final product is also compostable, allowing the production of fertilizers. The standard method used for measure the compostability of Biocouro was ISO 20200, which determines the degree of disintegration under simulating composting conditions. This method was initially developed for measure the disintegration of plastic materials. Usually, even for plastics called "biodegradable", 100% of disintegration is obtained only after 45 days of incubation. Generically, the leather in the market, wet-white (chrome free), vegetable or wet-blue based, reach 100% of disintegration only after 30 - 50 incubation days, and in the case of wet-blue based leather, the chemical composition of final compost does not allow its application in fertilizers production, in consequence of the high chromium content.
During test according to ISO 20200, leather pieces are introduced in a composting mixture with: sawdust; rabbit-feed; ripe compost; corn starch; saccharose; corn seed oil; urea. All this composting mixture is putted in a reactor with standardized dimensions. During the test, the reactor is putted in an air-circulation oven maintained at a constant temperature of 58 +2 °C. In Curtumes Aveneda, after a long period of R&D work, testing different tanning and wet-end processes, and assuring a complete technically metal-free process, Biocouro is a biodegradable product. 100% of disintegrability is obtained in less than 30 days.
