Synthesis and dyeing properties of indophenine dyes for polyester fabrics

In this study, a series of indophenine dyes (D1-D6) that show high molecular planarity, were synthesized and applied as dyeing materials for poly (ethylene terephthalate) fabrics. The relationship between the dye molecular structure and dyeing properties, such as dyeing rate and color fastness properties, was investigated. Compared with conventional azo or anthraquinone dyes, the indophenine dyes had a much lower dyeing rate but very good anti-thermomigration properties. This phenomenon indicated that there exists much larger intermolecular interaction between indophenine dye molecules, which was also confirmed by the results of quantum chemical density functional theory (DFT) calculations. The substituent effect of alkyl groups and halogen atoms (F and Cl) was also investigated. The steric hindrance of linked ethyl groups could efficiently promote dyeing performance, while halogen atoms lowered the color acquisition. As a result, D4 with only two N-ethyl groups incorporated on the indophenine backbone showed the best overall dyeing performance.