The Use of Cationized Cotton To Improve the Cotton Dyeing Process

Summary

Cotton garments continue to be a popular choice with consumers desiring the feel and comfort of natural fibers. However, all current dyes for cotton exhibit only a moderate affinity for the fiber. In order to apply cotton dyes in reasonable color yields from exhaust processes, significant amounts of dye bath electrolytes are used and long dyeing cycles are employed. In addition, extended washing procedures are required to achieve acceptable colorfastness to crocking and laundering. For direct dyes, a polymeric fixative agent must be applied to improve washfastness properties to minimum levels. The overall cotton dyeing process is energy and water intensive and leaves significant amounts of color and chemical waste in the dye house effluent.
Attempts to improve the affinity of dyes toward cotton include new dyestuff synthesis, new equipment development, and chemical modification of cotton fiber. Of these approaches, the last will permit improved cotton dyeing with existing dyes and dyeing equipment, important considerations in the current economic climate.
The most successful fiber modifications involve inserting cationic sites into the cotton fiber. This report will present the dyeing behavior of cotton that had been rendered cationic by reaction with 2-3-epoxypropyltrimethylammonium chloride. Prior work with direct, fiber reactive, acid, and natural dyes will be summarized and new data will be presented on color yield and colorfastness properties of cationized cotton dyed with vat and sulfur dyes. Excellent dyeing results were observed without the need for dye bath electrolytes or extended washing procedures.

This paper was first published on the earlier Egytex website. The text above is the summary that was published there.