Our recent Two Truths article challenged popular binary beliefs that alternative 'leathers' are 'more 'sustainable' than animal leather. In reality, for as long as the beef industry exists, cowhides will too, and disposing of them without inflicting environmental damage is impossible.
However, for leather to be viable long-term, its processes require modernisation, says leather industry expert Dr Luis Zugno. His career began in 1974 in tanneries in Brazil before he gained a PhD, specifically in leather technology, at the University of Cincinnati in the US. He is now the Global Innovation Manager at Buckman Chemical and one of the foremost independent educators on leather production.
Alongside Dr Zugno is input from Asim Khan, designer and artist whose creative process is grounded in material research and development, which he does for Ecco, Stone Island and other brands.In this expert opinion piece, we share problems, potential solutions and roadblocks to leather modernisation and impact reduction.
During his 47 years of dedicated service to the Leather Industry, Dr Luis Zugno has used his education and experience to advance the technology and science of leather manufacturing worldwide. His experience includes product development, project management, scientific work and hands-on leather manufacturing in large tanneries. Dr Zugno has been an active member of leather organizations. He is now the Secretary and former President of IULTCS and Management Board member of Leather Naturally.
Our recent Two Truths article challenged popular binary beliefs that alternative ‘leathers’ are ‘more ‘sustainable’ than animal leather. In reality, for as long as the beef industry exists, cowhides will too, and disposing of them without inflicting environmental damage is impossible.
However, for leather to be viable long-term, its processes require modernisation, says leather industry expert Dr Luis Zugno. His career began in 1974 in tanneries in Brazil before he gained a PhD, specifically in leather technology, at the University of Cincinnati in the US. He is now the Global Innovation Manager at Buckman Chemical and one of the foremost independent educators on leather production. Alongside Dr Zugno is input from Asim Khan, designer and artist whose creative process is grounded in material research and development, which he does for Ecco, Stone Island and other brands.
In this expert opinion piece, we share problems, potential solutions and roadblocks to leather modernisation and impact reduction.
Industry infrastructure
Regarding infrastructure, a fundamental limitation is that the countries producing beef are not the same as those producing leather. Beef is produced mainly in Brazil and the US, with global meat sales highest in the US1 and Europe. Leather production, by contrast, is most widespread in Asia, with the exceptions of Brazil and Italy.
Most hides are shipped from the source country to the tanning country. Because of the delay in tanning, these hides require temporary preservation that halts biodegradation during transit and storage. Dr Zugno explained that these hides are packed in salt, sending shipments soaring in weight and increasing transport emissions. Furthermore, the salt adds a cleaning step once the hides reach the tanneries, increasing water use, processing time, and costs. Another consequence is the excessive salt levels in wastewater, which can lead to other environmental impacts if not treated effectively.
Dr Zugno believes that rising import and export regulations and the heavy processing burden on recipient countries will eventually lead to the rejection of salted hides. He explains that China, for example, suffers from increased water salinity with additional environmental knock-on effects from processing these hides. The US, in particular, would be required to expand its tanning and finishing infrastructure to process hides in-country if China and others rejected salted hides on environmental grounds, he added.
Brazil is one such country where the export of untreated hides is illegal, meaning that all hides from Brazilian beef cattle are tanned, dyed and finished in Brazil. This is one example where sourcing Brazilian leather has inherent impact reduction during the fresh hide to finished leather stages due to the elimination of transportation and salt processing.
In the US, a lack of economic incentives for processing hides in-country could be addressed by exporting them to nearby Mexico, says Dr Zugno – this could avoid salting and leverage the tanning infrastructure there. That, of course, would still transfer the environmental burden of leather processing to another country, albeit with lower impacts.
Material ‘norms’
On the ‘material norms’ front, the industry veteran explains that convention has dictated that leather be chemically treated to levels beyond what its use and lifespan demand. “We are making leather too good – making it last forever – maybe there is no need for that. Our objective should be to make a product optimised to biodegrade at [the] end-of-life.”
But why is leather being overprocessed? The scientist says that brands demand particular aesthetic qualities in leather, despite the increased impacts. “Sometimes brands [ask for] requirements that don’t make sense. The dyes are the most toxic materials for the textile and leather industry [but] brands demand dye through the entire skin, [rather than simply in the visible surface layers]”.
The consequence of this practice is a cascade of increased impacts: higher chemical use leads to increased water use and, therefore more intensive wastewater treatment, which causes higher energy use – resulting in higher carbon emissions. The solution, however, may be less innovation-driven and more to do with communication between tanneries and brands to set expectations based on what is needed rather than what is conventional.
Leather is first tanned, then dyed and lastly finished. It is the second and third of these processes that impede leather’s biodegradability. The swiftest and best opportunity here, says Dr Zugno, is for the end-users of leather to work very closely with tanneries, with complete visibility of the impacts versus material properties, to optimise dyeing and finishing according to the leather product being made. In doing this, chemical formulations and applications can be rebuilt from the ground up, he says, creating new recipes that significantly reduce impact and increase biodegradability due to the removal of traces of harmful chemicals typical of overzealous dyeing and finishing.
Another leather impact reduction opportunity is vegetable tanning in place of chrome or synthetic tanning agents. Vegetable tanning is the oldest commercial method of making leather, using plant extracts (‘tannins’) from roots, leaves, fruits, bark, wood and seeds from cultivated sources. This tanning avoids toxic heavy metals (Chrome 6), but the leather is usually heavier and firmer than chrome-tanned versions, and requires particular manufacturing methods. In addition, vegetable-tanned leather has less resistance to water and is not washable – another drawback compared to chrome-tanned leather. These limitations make it less suitable for some footwear applications, for example.2
Dr Zugno also qualifies the scope of vegetable tanning when explaining that there are not enough plant tannins available from cultivated sources to convert all tanning to vegetable-based, even if it was viable in material and product terms. “There is no way to resolve this within the next 10-20 years,” he says. ‘Wet white’ tanning (chrome free) is also a lower impact option. However, it creates leather with properties best suited to the automotive industry, where it makes dashboards and seats.
Design innovation
On the design innovation side, leather should be reimagined creatively and combined with other materials, the Global Innovation Manager believes.
“Why aren’t we using half the thickness of leather and bonding it to other materials or fabrics to create [enhanced] composites?” Dr Zugno asks. His comment returned my thoughts to the recent conversation with Luke Haverhals when he explained how bonding NFW’s plant-based ‘leather’ to cellulose fabrics enhances overall material performance. Both these experts share a similar mentality regarding innovation: to creatively and collaboratively apply science’s ‘material rules’ to make best-in-class materials dependent on use and end-of-life.
There seem to be pockets of such design innovation, though, as demonstrated in my coverage3 of transparent, indigo-dyed and direct plant printing on leather by designer Asim Khan, who is part of the leather development team at Ecco. The same company also made the news this week with an in-house design collective in their Netherlands tannery developing leather applications.4 During an interview with Khan he said: “What I am trying to do is reinterpret leather – to create something that is beautiful and will last forever”. Within Ecco, Khan’s work is structured around impact and aesthetics. The innovation team develops iterative leathers to present to brands, accompanied by their respecitve impact assessments. Recent developments include organic formulations for finishing leather, in place of synthetic ones. In this way, the tannery informs and suggests low-impact options through background research and development.
Dr Zugno’s insights indicate that regulations and import/export restrictions have a role to play in reducing leather industry impacts. On the material side, he calls for new ways at an industry level of stabilising hides that find a ‘chemical sweet spot’ (based on needs) and creating composite materials that utilise leather in a more modern, creative way and low-impact way.
The biggest roadblocks to these solutions, he says, are fixed mindsets. “We have to open our minds – if you aren’t creative, you can’t imagine a new way.” Sharing another glimpse of his innovation mindset, Dr Zugno predicts that “somebody outside the leather industry is going to reimagine what we can do with the proteins [in hides] – and in particular the collagen that we currently process into leather”.
