Evaluation of Washing Durability of Non-Fluorinated Water-Repellent Finishes on Firefighter Protective Fabrics

This study investigates the washing durability of non-fluorinated water-repellent finishes applied to aramid based protective fabrics intended for firefighter protective clothing. Water repellency was evaluated as a function of repellent concentration (20, 40, 80 g/L), catalyst content (10, 20, 40 wt%), curing temperature (130, 150, 170 °C), and washing cycles (0, 5, 10, 20 cycles). Spray rating was assessed following ISO 4920 across all processing conditions, while static contact angle measurements (ASTM D5946) were conducted at a representative concentration of 40 g/L. Four-way ANOVA demonstrated that repellent concentration, catalyst level, curing temperature, and washing cycles had statistically significant effects on spray rating (p < 0.001). For contact angle, curing temperature and washing cycles were significant factors (p < 0.01), whereas catalyst content showed no significant influence. Although spray rating and contact angle exhibited a positive correlation at 40 g/L, this correlation weakened after repeated washing due to partial disruption of the coating layer. The results indicate that water-repellent finishes applied at 40-80 g/L, combined with catalyst levels of 20-40 wt% and curing temperatures of 150-170 °C, provide favorable washing durability. Furthermore, the spray rating method was found to be a more reliable indicator of practical water repellency than contact angle measurements for firefighter protective fabrics.