Synthesis and application of dyes derived from Schaeffer’s acid on nylon 6,6 fibers

Abstract

A monoazo dye was synthesized and applied to nylon 6,6 fibers. The effect of heat-set and auxiliary treatment on the absorption of acid dyes by nylon fibers was investigated. The dye was synthesized by the diazotization of primary amine to form a diazonium salt and coupling it to a coupling component (Schaeffer’s acid). The effect of increasing heat-set time at 200, 210, 220 and 230oC, was investigated. The effects of increasing temperature of heat-set at 90 seconds, auxiliary concentration and dyeing time respectively were also investigated. Exhaustion dyeing method was used in all the investigations. The results showed that as the heat-set time increased percentage exhaustion decreased, indicating that the nylon 6,6 fibers were getting nearer to their glass transition temperature (Tg). The effect of increasing acid concentration showed that 3% acid concentration gave the maximum percentage exhaustion with increasing time, but as the acid concentration increased, the dye began to go out of the fiber. Specifically, at 40 minutes the shade was deep but at 5% concentration with increasing time of dyeing, the liquor darkened and the color that was absorbed got stripped-off.

Keywords: Monoazo dye, Schaeffer’s acid, diazonium salt, nylon 6,6 fibers,