Optimization of the application of cationic agent in the screen printing paste with reactive dye on cotton substrate

Reactive dyes stand out for their bright shades, excellent fastness properties, and soft touch in the screen-printing process with cellulose. However, reactive dyes have a low affinity for cellulose. Therefore, this study aimed to apply the cationic agent 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC) in the preparation of the reactive dye solution red 245, to improve the conduction of the screen-printing process and the fixation of the dye to fiber. In this process, a Box-Behnken Design was used to investigate the effect on concentrations of cationic agent (40, 60, and 80 g/kg), urea (75, 100 and 125 g/kg), and sodium carbonate (20, 30, and 40 g/kg). The study analyzed the paste pH, viscosity, zeta potential, color intensity, % penetration of prints, and dye concentration in the washing baths after the printing process. The study determined that the optimal levels for these factors were 60 g/L for the cationic agent, 100 g/L for urea, and 30 g/L for sodium carbonate. The optimization of the printing paste proved to be a great alternative to help in the color yield and penetration percentage of the prints, minimizing the use of urea, alkali, and cationic agents in the printing pastes.