Increasing the waterproof performance of fatliquored leather by silane modification: a simple and feasible green treatment method

Abstract

Waterproof fatliquoring agents can transform leather from a hydrophilic state to a hydrophobic state in the wet process of leather production. However, traditional waterproof fatliquoring agents may cause environmental pollution. Fluorocarbons in fluorinated fatliquoring agents are difficult to degrade, and polyacrylic acid fatliquoring agents require chromium powder fixation. In this work, we proposed a simple and green leather waterproofing strategy through the wet process. The strategy used silane coupling agents, water, and ethanol to waterproof the fatliquored leather. The results indicated that leather exhibited excellent waterproof performance when treated with 20% hexadecyltrimethoxysilane (TMS16), 20% water and 300% ethanol at 30 °C for 6 hours. The water contact angle (WCA) of leather was greater than 120° and maintained lasting hydrophobicity, which can still sustain a high contact angle after 30 minutes. In addition, the physical properties of the leather were significantly improved. After the TMS16 treatment, the tensile strength of the leather increased from 4.82 MPa to 12.45 MPa, the tear strength increased from 77.07 N mm⁻¹ to 125.01 N mm⁻¹, and the elongation at break increased from 47.03% to 66.71%. This leather waterproofing strategy is environmentally friendly, and the process is simple.