Dr. Peter Hauser, associate professor, North Carolina State University (NCSU), College of Textiles,
Raleigh, N.C., is developing a greener process, cationic fiber modification, for cotton
dyeing.Sponsored, in part, by Dow Chemical Co., Midland, Mich., Hausers research involves treating
the cotton with the Dow chemical, N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride. The
permanent positive charge on this cationic chemical provides a permanent site to attract
negatively-charged cotton dyes. Because of the small molecular size, however, the chemical cannot
be exhausted from a batch process prior to dyeing.The new process is much more efficient and saves
about half of the time normally required to dye cotton, said Hauser. It uses one-third of the
energy and only 20 percent of the water used in traditional methods, and no salt. In addition, less
dye is needed as a result of the strong attraction of the dye to the surface of the fiber.The next
phase of Hausers research involves developing ways to streamline the new process to make it a
continuous process that does not slow down production in dyeing and finishing.
October 2001
