Dyeing of jute with binary mixtures of jackfruit wood and other natural dyes - Study on colour performance and dye compatibility

摘要

Varying proportion of binary mixtures of aqueous extracts of jackfruit wood (JFW) with other natural dyes, like manjistha (MJ), red sandal wood (RSW), mariegold (MG), sappan wood (SW) and babool (BL), have been used to dye bleached jute fabric pre-mordanted with 20% myrobolan followed by 20% aluminium sulphate. Binary combinations of JFW with each of the five natural dye extracts have been evaluated for colour strength (K/S value) and its coefficient of variation, brightness index (BI), changes in hue (△H), metamerism index (MI), total colour differences (△E) and colour fastness to washing , light and rubbing. Dyed fabric samples have been further treated with the cationic dye fixing agents n-cetyl-N-trimethyl ammonium bromide, cetrimide and Sandofix-HCF to improve wash fastness. Treatment with 1% benztriozale is also given to improve light fastness. The compatibility of these binary pairs has been assessed by the analysis of △C vs △L and K/S vs △L plots for the progressive depth of shade produced by varying time and temperature profile as well as by varying total concentrations of the binary pairs of dyes taken in equal proportion. A simple method of assessing relative compatibility rating of pairs of dyes has been proposed, where a new index called colour difference index [(△E x △H) / (△C x MI)] has been postulated and the compatibility ratings determined. The results of this proposed system of compatibility rating are found to be in well agreement with the results of conventional methods of plots analysis. The order of relative degree of compatibility of these binary pairs of natural dyes applied on pre-mordanted jute is found to be JFW : RSW ≥JFW: BL ≥JFW : MJ > JFW: MG > JFW : SW.