Effect of Alkali Concentration on Dyeing Cotton Knitted Fabrics with Reactive Dyes

The effect of alkali concentrations has been studied on the color strength (K/S) and color fastness properties of single jersey cotton knitted fabrics dyed with 1% Novacron Red S-B reactive dye. Same bath scouring and bleaching are performed and conventional exhaust dyeing method employed by IR laboratory sample dyeing machine. Various alkali concentrations such as 6, 7, 8, 9 and 10 g/L are employed and other parameters are kept fixed. The color strength (K/S) and color fastness to wash and rubbing are examined and evaluated. It is revealed that with the increase in alkali concentration from 6 g/L to 8 g/L the value of K/S increases and then up to 10 g/L the value decreases. The overall color fastness properties to washing and rubbing for the dyed samples range from good to excellent.