Synthesis and its application on fabrics of disperse dye-encapsulated with waterborne polyurethane (WPU)

Utilizing waterborne polyurethane (WPU), the commercial dyes disperse red 60 (R60), disperse yellow 54 (Y54), and disperse blue 56 (B56) are encapsulated to form micelle structures. When applied to fabric dyeing, this approach effectively enhances properties such as colorfastness and resistance to dry and wet rubbing. Commercial disperse dyes were physically encapsulated using WPU to form micelles in a water medium. The structures of the encapsulated dyes were confirmed using 1H-NMR and FTIR spectroscopy. The average molecular weight (Mn) of the materials ranged from 2.2 × 104 to 2.9 × 104 g mol−1. UV-visible (UV-vis) spectra comparisons before and after encapsulation showed no significant color shift, indicating minimal alteration of the original dyes. However, all dye-WPU samples exhibited a notable quantum yield of 41% in the fluorescence spectra and displayed higher thermal stability compared to the dyes without WPU. The electrical layer on dye-WPU particles enhanced fluorescence intensity. Zeta potential measurements confirmed particle stability (-32 to -55 mV). Micelle size ranged from 70-150 nm. Encapsulated dye-WPU showed improved thermal stability and Tg of −58 to −65 °C. Applied to fabrics, especially cotton, dye-WPU exhibited excellent color fastness and resistance to thermal migration in immersion or digital printing.