Staining behavior of azo disperse dyes on the cotton component in polyester/cotton blended fabrics during nonaqueous medium dyeing

A recent development in salt-free and reduced water dyeing technology for polyester and cotton has been applied in the dyeing industry. However, an issue of color staining on cotton fibers during the disperse dyeing process has been observed. To address this issue, staining behavior of azo disperse dyes on cotton components in the nonaqueous medium dyeing system was investigated. It was observed that the C.I. Disperse Blue 257 exhibited greater stability and less propensity for decomposition or color change compared with C.I. Disperse Blue 183:1, resulting in reduced loose color and enhanced durability during the dyeing process. For polyester component dyeing, the dyeing temperature has a highly significant effect on the final uptake of dye. However, for the cotton component, the results showed that acetic acid has the most significant effect on the staining of disperse dye. The strong intermolecular interactions inherent in cellulose molecules, which results in the dye adhering primarily to the exterior of the cellulose structure. The contribution of electrostatic forces to intermolecular attraction is significantly heightened due to the abundance of hydroxyl groups present on the cellulose molecular chain. From investigating the uptake and staining performance of disperse dyes, this study elucidates the mechanism of color staining behavior of disperse dyes on cotton fibers, demonstrating the potential of a one-bath two-step dyeing process in a nonaqueous medium dyeing system.