It's leather but not as you might know it

摘要

We all know what leather is, where it comes from, and the intrinsic qualities and properties it naturally has. "The hide or skin from an animal, with its fibrous structure more or less intact and tanned to be imputrescible" was one of the first things most young leather students would learn, verbatim. This statement, taken from the British Standard BS 2780, also goes on to cover other elements. Most recently, however, the focus on the imputrescible nature of leather has been the subject of many conversations. Leather has a long and varied history. Smoke, fat and brain, vegetable tanning, all vying for possible and probable founders of the technology but no one can be absolute in knowing this. What we do know is that, ultimately, the preservation of hides and skins has been part of hominin history for tens of thousands of years. Archaeological discoveries in 2021 of prehistoric bone scraping tools found in caves in Morocco dating back over 90,000 years provide hard evidence. By the early 1900s, when chrome tanning had been established, the seemingly perfect fail-safe test of tannage was found - the boil test. This was a simple yet effective measure of complete tannage. Until that time, the vegetable, alum (tawed) and oil tanned leathers all gave varying levels of hydrothermal stability but were deemed sufficient for what they were to be used for. It now seems that whilst we argue that "alternatives" to leather should not be called as such - they are far from the definition of leather - we now find ourselves in an interesting position where the definition we hold so dear might need to be tweaked. For certain applications, the longevity afforded by tannage is essential. In this instance, the durability of the product means that it could be used, repaired, reused, and re-loved by someone else and certainly not likened to the longevity of a plastic bag where plastic will slowly fragment into smaller and smaller microplastics, pervading the natural environment. However, this "tannage timeline" is not necessary or even relevant for many applications today. Where the beauty of a leather bag, handed down from generation to generation strikes at the heart of the value of both the product and the leather itself, the same is not necessarily true for the leather upholstery in a car, which will most probably outperform the life of the engine, electrics and bodywork but there is very little sense in buying a car purely for the degradability of a leather interior and even less in looking at it as an heirloom. There are, of course, other desirable properties but In this specific way, the requirements and function of the leather are totally different.