Study on enhancing the union dyeing of cotton/modal blended fabrics with cationic modifier

Cotton/modal blended fabrics are favoured by the market because not only do they have the advantages of the dimensional stability of cotton and drape wear resistance of modal, they also overcome their shortcomings, displaying a sense of stiffness and smooth feel. However, because of the differences in the physical and chemical properties between each component, the dyeing of blended fabrics with reactive dyes is prone to problems such as low fixation percentage, different dyeing percentages and colour depth. Here, two cationic modifiers, 2,3-epoxypropyltrimethyl ammonium chloride (GTA) and methaacryloyloxyethyltrimethyl ammonium chloride (DMC), were applied for cationic modification of cotton/modal blended fabrics, and their role in the dyeability and union dyeing of cotton/modal blended fabrics was studied. The results showed that the K/S and fixation percentage of the blended fabric treated with GTA and DMC cationic agents could be significantly improved compared with the control group, and that the colour fastness of the blended fabric can reach grade 4-5. Compared with GTA, DMC-modified cotton/modal blended fabric showed better union dyeing properties because of its better diffusion performance in the fibre. The mesoporous volume of the cotton fibre is higher than that of the modal fibre, while the micropore volume is the opposite. Consequently, DMC macromolecules, through free radical graft polymerisation, were more likely to diffuse into cotton fibres with more mesoporous content, increased the interaction force between anionic reactive dye and cotton fibre, and improved the dyeability of the cotton component and the union dyeing performance of the blended fabric.