EVALUATION of Fastness of the Colorant COCHINEAL against to Synthetic Colorants Applied ON Cotton Fabric.

Nowadays the worldwide textile industry is searching how to replace the synthetic colorants with natural colorants, for that reason every time is higher the quotation on the market of the natural colorant cochineal. The objective of this research work was to evaluate the fastness of the colorant cochineal applied on cotton fabric. In order to verify this fastness, five tests were realized, which consisted of submitting the dyed cotton fabric to: acid and alkaline solutions, high and low temperatures, household washing, artificial light and dry rubbing. The results obtained in the experiment were compared with the results obtained from a cotton fabric dyed with a trichromatism of synthetic colorants (Remazol Golden Yellow RGB, Novacron Scarlet and Novacron Red C2G) and submitted to the same fastness tests. It was observed that the percentage of lost color in the cotton fabric dyed with the trichromatism of the synthetic colorants previously mentioned, is minor in the three coordinates of the scale CIELAB (L*, a* and b *), than the percentage of color lost in the cotton fabric dyed with cochineal, with an average significant difference of all the fastness tests for the coordinate L* of p=0.027, for the coordinate a* of p=0.013 and for the coordinate b* of p=0.018 (p≤0.05, α =0.05). So, it is deduced that the color fastness in the cotton fabric dyed with cochineal is minor than in the cotton fabric dyed with the trichromatism of synthetic colorants. Even so, due to the added value that is given to the finished product on having dyed with natural colorants, in addition to its harmlessness for human being, it is suitable to adapt this process at an industrial level.