Study on Light-colored Vegetable-tanned Leather Processing and Dyeing Techniques

Abstract

Leather has played a pivotal role in the advancement of human civilization, spanning from enhancing early survival techniques to fostering economic, military, and cultural growth. It continues to be a vital material in contemporary industries, including fashion. In the realm of leather tanning, predominant methods have historically centered on chrome tanning and vegetable tanning. The inception of chrome tanning by German chemist Friedrich Knapp in 1858 marked a significant milestone, leading to the advancement of application methodologies to a sophisticated level. However, given the adverse effects of chromium, a heavy metal, on human health and the environment, there is a pressing demand within the industry for alternative, eco-friendly technologies to supplant chrome tanning [1]. Vegetable tanning, an environmentally friendly method, is benign to both humans and the environment. Nonetheless, vegetable-tanned leather is constrained by its reliance on vegetable tannins, resulting in a predominantly dark hue that fails to satisfy the varied color preferences of the market. Therefore, the creation of a vegetable-tanned leather with a lighter shade holds substantial importance [2]. This study compared different tanning agents: phosphate salt, zeolite, glutaraldehyde and synthetic tanning agent pre-tanning, made white wet hides, reduced the amount of tannin extracts, and then used lighter tannin extracts for retanning. By comparing the hue of the leather crust and some basic physical properties, it was found that pre-tanning with 2 glutaraldehyde and synthetic tanning agents, followed by retanning with ATG and MIMOSA, the leather crust had a lighter hue and the physical properties could meet the product requirements.