Comparison and assessment of selected parameters of chrome-free and chrome-tanned leather

In the leather tanning industry, decision-makers act resolutely to eliminate chrome as a tanning agent due to its negative effect on human health and the natural environment. Considering this, it makes sense to research opportunities to use chrome-free leather as a substitute for chrome-tanned leather. This paper demonstrates research on the mechanical and hygienic properties of leather tanned with glutaraldehyde as well as chrome-tanned leather, intended for shoe uppers. The results of the tensile strength and percentage extension measurements made by the Instron tensile machine, and the results of water vapour permeability measurements made by a moisture analyser, have been analysed using Statistica. The statistical data analysis has been performed using the following tests: Kolmogorov-Smirnov with Lilliefors correction, Shapiro-Wilk, T, Levene, Brown and Forsythe, Fisher-Snedecor, and Cochran-Cox. Regarding mechanical parameters, no statistically significant difference has been observed between chrome-free and chrome-tanned leather in dry conditions. However, such differences have been observed in wet samples. The tests showed higher stability of mechanical parameters of leather tanned with modified glutaraldehyde compared to chrome-tanned leather. Leather tanned with a chrome tanning agent, tested in both dry and wet conditions, showed significant differences between them, considering their tensile strength and percentage extension. The hygienic properties of both types of leather being researched are more or less similar – the research has not found any statistically significant differences for water vapour permeability.