Minimization of Process and Wastewater Load in a Low-Pressure Environment through Vacuum Application for Fiber-Based Materials: Leather and Cotton Products

Our study aimed to eliminate the negative aspects of conventional fiber-type materials. First, leather dyeing was considered by designing a vacuum-operated reaction vessel/drum and a suitable production recipe for sheepskins, based on the analyzes of float uptake and color strength regarding water usage, dyestuff usage, and process time. Acid dyes were used for leather dyeing under a vacuum. The dyeing time decreased from 60 minutes to 30 minutes with the application of low pressure. Float uptake increased from 71.18% to 92.02% by analyzing the residual dye floats with a 30-minute vacuum process. Process water was considerably saved, and float water eliminated. The success of the process was demonstrated by float uptake and color strength (K/S) values after dyeing. Metal complex and cotton dyeing applications were also conducted under a vacuum to demonstrate the system's effectiveness on fiber-type products. The results showed that vacuum-operated dyeing procedures were highly effective and promising for the sustainable production of fiber-type materials.