Hot topics - the 119th SLTC Conference

Chrome VI and the future use of chrome in leather manufacture

This was the theme of a debate held with the audience providing questions and then discussed by the panel. The panel, comprised of Dr Dietrich Tegtmeyer (Lanxess), Emeritus Professor Tony Covington (ICLT), John Hubbard (SATRA), Geoff Holmes (LASRA) and Dr Kerry Senior (UKLF), was chaired by Reg Hankey of Pittards. The panel discussed and answered a wide range of questions with the defining outcomes being that if sourcing chrome tanning chemicals from reputable suppliers is done and leather is sourced from responsible leather manufacturers who follow best practices, chrome VI is today a perfectly manageable risk. Some finer details remain to be solved, leaving the industry with impaired communication, perception and the confidence of the brands and consumers. Yet, the industry is in a much better place than last year or before.

The future of vegetable tanning

The past, present and possible future of vegetable tannage was discussed by Nigel Payne of Forestal Mimosa. The decline in the use of vegetable tanning from 450,000 to below 150,000t from the 1950s to 2000s respectively reflects the change in shoe design and of the use of chromium. Today, more vegetable extract is used in retannage. Payne also commented that while there are hides available to tan, there will always be a demand for vegetable extracts. In fact, this point was highlighted during the Chrome Panel debate as vegetable extracts are increasingly being applied.

Digital printing on leather

This subject was presented by Dr Barry McGregor from Fujifilm Speciality Ink Systems, a company with $27-billion global revenue and an R&D budget of $7 million a day. McGregor showed how a company like Fuji analyses potential markets and how it sees a potential for digital high-value printing ink sales of 1.9t/year in this niche market. He also detailed a significant amount of work performed by Fujifilm, in a highly competitive market, to focus on printing with a precursor (pin) layer using hybrid UV inks and a top coat to achieve the print quality and physical properties required of shoe-upper leather. He then spoke of various machine applications and available ink technologies.

A sustainable future for the leather industry

This was presented by Mike Tomkin, supported by STAHL. He has recently retired but was kind enough to support the conference and present his thoughts on the future with the clear objective of ‘being able to meet the needs of the present without comprising the ability of future generations to meet their own needs’. Corporate social responsibility should be a standard strategic business operation as businesses must take responsibility, as well as consumers and governments. Leather processing does not need to be a dirty operation with high water, chemicals and energy use – there is room for improvement and LWG-rated tanneries are clearly demonstrating significant improvements. Regarding disposal or recycling, Tomkin explained that landfill is not likely to be an option in future, and the life cycle of leather and its disposal needs to be addressed proactively.

The proctor memorial lecture: From sheep yards to SNP (single nucleotide polymorphism) chips

The changing face of raw-stock research at LASRA was given by Dr Sue Cooper, FSLTC from LASRA, New Zealand. She shared by describing her work on raw stock research to ultimately improve final product quality. Examples and facts showed how, for example, cockle levels in sheepskins have reduced from 10 to 2%, and how the removal of barbed wire does not reduce the incidence of scratches on cattle, but optimised management of lice on cattle does. Current research into genetic markers on sheepskins was highlighted, using SNP chips to identify genetic value while the animal is still alive for future breeding, and carcass weight among others. LASRA has been evaluating the resultant skins from this research.

Water-saving processing

The leather industry is an intensive user of water, and Karl Flowers (ICLT, Northampton University) described the physics and chemistry of water properties, and the tannery usage of water being in the region of 25m3/t of raw material. The water footprint calculation includes blue, green and grey water, but Flowers also explained virtual water, which calculates the direct water use in manufactured goods that are sold/transported and that should also be included. Alternative technologies to water were discussed and the problem of the density of leather in processing. Water affinity and mass transfer was highlighted in relation to the penetrative stages of wet processing. Future technologies as closed-loop recycling, chemical treatments and biological scrubbing, deep shelf drum processes and continuous process operations (for example, through-feed dyeing) were also covered.