Ecosustainable leathers with HydroilA new line of antioxidant products deriving from olive mill wastewater for a metal-free process
Dermochimica has launched Hydroil, a new line of products for the tanning and retanning process based on recovery waters coming from the production of olive oil. The new system, the object of two patent applications, does not use metals but allows to obtain leathers with high-level characteristics and performance comparable to chrome tanning. Hydroil can be used as a chromium (VI) inhibitor in the retanning phase or in the whole process to tan in total absence of chromium. The tanning process turned out to be valid on leathers intended for all production segments, from the footwear to the automotive sector, from leather goods to furnishings.
The history that led to the development of this new line of products is worthy of interest: Hydroil is the result of an Italian research project conducted through newco Tannow. Started a couple of years ago, the research was born with the aim of developing products of natural origin for the tanning sector, starting from the by-products of the agri-food industry. The proposed innovation was the following: re-use OMWW (Olive Mill Wastewater) to develop products with a tanning and antioxidant effect to make metal-free leathers and that are wet-blue base resistant to the formation of Cr VI. All this starting from a fundamental consideration: Italy is one of the most important world producers of leather goods and the second largest producer of olive oil in the world.
But let’s see how two industrial needs have happily met in a circular economy perspective. Olive Mill Wastewater (OMWW) derives from the production of olive oil and is among the most polluting agro-industrial wastewater, containing in reality phenol and polyphenolic compounds with a high antimicrobial and phytotoxic action and it would be a pity not to value them. The main phenolic compounds present in OMWW are hydroxytyrosol, tyrosol, catechol, methylcatechol, oleuropein, caffeic, gallic, vanillic and coumaric acid, which have extraordinary antioxidant properties. Among other things, natural tannins with tanning action are already present in OMWW. Consider that hydroxytyrosol can constitute up to 50% of total OMWW polyphenols and that is has been recognised as one of the most potent antioxidants in nature, about ten times greater than green tea and at least twice as high as CoQ10. And there is a huge quantity of olive mill wastewater, just think that from 100 kg olives are obtained 20-22 kg of olive oil and 50-80 kg of OMWW. At European level, in 2014/2015 were produced about 4.8 million tons of OMWW, which need to be disposed. Hence the solidity of the project also on an industrial level.
To conclude, the results of the research were in line with the best expectations. The tanning power of Hydroil turned out to be comparable to that of natural tannins. In addition, the antioxidant power of Hydroil on wet-blue retanning reduces the formation of Cr VI by 50% thus allowing the replacement of all synthetic retanning agents that contain formaldehyde.
Covered by secrecy, the innovative tanning system produced by Tannow and distributed by Dermochimica is awaiting the recognition of two patents. Productions made in the tannery have given excellent results not only in terms of low environmental impact of the, completely metal-free, tanning process but also for the quality characteristics of the finished leather similar to those treated with chrome.