2010-The Significance of Variations in Liquor Ratio on Sorption of Reactive Dyes in Admixture applied to Cellulose

The Significance of Variations in Liquor Ratio on Sorption of Reactive Dyes in Admixture applied to Cellulose

Mehmet Ozturk, Istanbul Technical University, Turkey


Real time dyebath monitoring and control devices have been proposed and employed over the last two decades to improve the efficiency of dyeing process and reduce associated operation and overall costs. While fiber reactive dyes are currently considered to be a common class of dye applied to cellulosic fibers, their introduction and subsequent application has resulted in a significant step forward in improving the overall performance of dyed cellulosic fibers.
This is due to their excellent wet fastness properties, exceptional brightness, wide range of available colors, and relatively simple application methods. Because of these attractive features, the demand for fiber reactive dyes has increased over the last several decades and they enjoy a comfortable share of the market and remain amongst the most important category of dyes applied to cellulosic fibers. However, in the reactive dyeing of cotton, a range of variables contribute to final exhaustion and fixation of dye onto the substrate which include the liquor to goods ratio, temperature, electrolyte concentration, pH, as well as the type of dyes employed.
It is a well known fact that variations in liquor ratio affect the depth of shade for a given concentration of dye. As the liquor ratio is increased, the dye’s tendency to remain in the aqueous medium also increases resulting in lowering the depth of shade of the dyed product. As such increasingly a larger number of dyeing machinery that can operate at low liquor ratios are employed in industrial settings with additional associated savings in water, chemical and energy consumption.
However, the control of levelness at lower liquor to goods ratios often requires additional care. In addition, it is important to bear in mind that variations in liquor ratio may not affect every dye to the same extent and that each dye will likely be influenced differently depending on characteristics.