Quality properties of leather produced in water and supercritical fluid (SCF) media

Supercritical fluid (SCF) technology is defined as green processing system and used in the industrial applications. This study aims to search the quality properties of leather produced in water and SCF media. Supercritical carbon dioxide (scCO2) was used as SCF. Tanning process was carried out by valonea tannin as natural tanning agent with different process time from 2 h to 8 h. After tanning in SCF, the skins were processed with conventional methods in water media and finished. Another group of the skins were just conventionally produced. ScCO2 tanned and finished leathers were compared with the leathers which completely processed in conventional ways as control group. Light fastness, tensile strength, tear load and stitch tear resistance analyses for the quality control of the products were carried out. Thermal stability characterization of the leathers were also done by differential scanning calorimetry (DSC) and mechanical shrinkage tests. The results showed that 2 h and 4 h of SCF-CO2 tanning applications were insufficient in terms of the physical properties expected, but 6 h and 8 h tanned leathers were in a good quality.