Cationic fiber reactive dyes for cellulosic fibers

The goals of this research were development of "zero electrolyte" fiber reactive dyes for cotton and simultaneous exhaustion and fixation of fiber reactive dyes for polyamide fibers. Two series of azo dyes were synthesized with varying electronic charge. In one series, a vinylsulfone (VS) group was incorporated into an azo chromogen. In the other series, a nonreactive ethylsulfone (ES) group was incorporated into the molecule in lieu of the VS group. The ethylsulfonyl moiety was a useful nonreactive analog of VS-based dyes. In the absence of electrolyte, the cationic fiber reactive dyes exhibited inherent substantivity for both cotton and nylon 6,6 under neutral or alkaline pH. In certain cases, level dyeings were achieved with high exhaustion and fixation levels. Cationic fiber reactive dyes offer potential for use in environmentally responsible fiber reactive systems.