Process Development and Optimization for High Efficiency Fiber Reactive Dyes for Cotton
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Date
2006-04-24
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Abstract
Fiber reactive dyes are important in dyeing textiles because they are unequally in their ability to confer bright wetfast shades on cotton fabric. While fiber reactive dyes are commonly employed for this purpose, the use of these dyes can introduce high costs and environmental concerns. For example, their fixation levels can be as low as 50% and high salt levels are typically needed to achieve desired shades. Thus, a mechanism for increasing fixation and exhaustion efficiencies in an economical way would enhance the value of these dyes to the textile industry. With these points in mind, researchers at North Carolina State University have studied a reactive dye modification that holds promise for achieving desirable exhaustion and fixation efficiencies. Specifically, the reactivity and affinity of some widely used dichlorotriazine (DCT) reactive dyes was enhanced using a straightforward 2-step process to convert commercial dyes to structures of types 1-4. In laboratory dyeing studying it was determined that type 2 dyes gave the best results in affinity and shade depth assessments. It remained to be shown that these dyes could be applied in an industrial dyeing setting.
This thesis research focuses on applying the type 2 modified dyes in a commercial-scale manufacturing setting in order to further assess the benefits of the modified dyes. In preliminary studies, laboratory-scale dyeings were conducted to further investigate the color strength relationships between the modified and commercial dyes. As the main thrust of this research, dyeings were conducted in the pilot plant at North Carolina State University in order to simulate a production environment. An optimized batch dyeing procedure was developed for the application of the modified dyes, including optimal temperature, salt and alkali concentrations, time, and bath ratio. It has been found that level dyeings can be readily produced using industrial scale equipment, and there was no adverse change in fastness arising from using the modified dyes in lieu of commercially available DCT reactive dyes. Further, it is clear that high fixation levels and deep shades are obtained using the modified dyes at lower dyeing temperatures and salt levels than commonly employed for the commercial dyes.
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Exhaust Dyeing, Dye Modification, Reactive Dyes, Cotton
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Degree
MS
Discipline
Textile and Apparel, Technology and Management
