Dyeing of jute with annatto seeds and other natural dyes

Abstract

Jute fabric samples have been dyed with aqueous solution of annatto (A) seeds along with three other natural dyes, viz. onion (O) skin, pomegranate (P) rind and marigold (M) flower petals. Varying proportions of binary mixture of these dyes have been used to dye jute fabrics which are mordanted with myrobolan and natural alum before dyeing. The dyeing performance is evaluated by measuring the colour strength and other related parameters along with the fastness properties of the dyed jute fabrics. The dyed samples are further treated with chitosan and n-cetyl trimethyl ammonium bromide (CTAB) to improve wash fastness. The treatments improve the wash fastness by 1 grade. The treatment of dyed jute fabrics with benzotriazole improves the light fastness by 1 grade. The compatibility of annatto dye with respect to other three dyes has also been assessed by plotting two different curves, viz. ΔC* vs ΔL* and K/S vs ΔL* for progressive depth of shade for each set of binary mixtures. These results are compared with a new parameter called Colour Difference Index (CDI). The results of CDI are in tandem with the results found from the plots, implying that the three binary pairs of natural dyes are comparable in different degrees.