Development of a Process to Prevent Back Contamination Caused by Cationization After Cationic Digital Reactive Printing on Cotton Knitted Fabrics

Due to the restricted fixation and hydrolysis of reactive dyes, digital inkjet printing on cotton materials presents difficulties with low color output and substantial wastewater formation. Cotton can be cationically modified to improve color strength, decrease salt requirements, and boost dye absorption and fixation. However, conventional two-stage cationization methods are time-consuming and water-intensive, and they frequently result in back staining when the cloth is washed, with unfixed colors discoloring the white (unprinted) portions. By adopting a rotary printing process to directly put cationic printing primer onto cotton knitted fabrics, this study explores a novel one-step method to address these problems. We created three distinct pretreatment formulations: two with varying quantities of sodium hydroxide and 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC) and a reference with no cationic ingredients. These formulations were applied to fabric, then digitally printed, air dried and steamed. In order to assess how well the printed fabrics prevented back-contamination, they were subsequently put through two distinct post-washing techniques; rope washing and open-width washing. The primary objective was to determine whether a combined cationization and printing process could simplify workflow and significantly reduce water and chemical consumption while ensuring print quality. The level of back contamination was assessed qualitatively by visually assessing the contamination of white areas after each washing process. The results from this study will provide important insights into the discussion on the industrial applicability of cationic cotton, particularly by addressing the issue of persistent contamination and exploring more sustainable, one-step processing solutions. The results obtained from this study contribute to the development of more efficient and environmentally friendly digital printing processes for cotton fabrics by providing important insights into the discussions on the industrial applicability of cationic cotton fabric, particularly by addressing the issue of persistent contamination in cationization and investigating more sustainable, one-step process solutions.