Dyeing nylon-6,6 with some hydrophobic reactive dyes by supercritical processing

Nylon-6,6 fibers, spun from the polyamide (polyhexamethylene diamine adipate), are increasingly required to he dyed with high washing fastness. Nylon-6,6 were dyed with hydrophobic reactive dyes synthesized in our laboratory, using supercritical carbon dioxide as the solvent system. Structures of four hydrophobic reactive dyes and their covalent force with nylon-6,6 fibers were confirmed by FTIR, MS and NMR analysis. Nylon-6,6 were also dyed with C.I. disperse red 2 to compare the result with specimen dyed by hydrophobic reactive yellowish red dye (dye 1). which further demonstrated that covalent force was formed between dye-fiber interaction. Dye uptake was moderate to good and the dyed fabrics had very good fastness properties. Results of the latter studies indicated that dyeing nylon-6,6 in supercritical carbon dioxide is feasible.