Dyeing of polyamide 6 fabric with new bio-colorant and bio-mordants

The present study investigates the natural dyeing of nylon fabric using the dragon's blood resin extract. Response surface methodology was used to optimize the process variables including pH (3-9), temperature (50-100 °C), concentration (10-50%owf), and time (30-90 min). From a visual point of view, diverse eco-friendly shades with a rather diverse color gamut of varied hue and tone were generated by applying a wide range of natural and eco-label mordants. The impact of 4 bio-mordants (including peppermint, mugworts (Artemisia), Dorema ammoniacum (DA) gum, and pomegranate rind), as well as 4 mineral mordants (alum, copper (II) sulfate, potassium dichromate, and iron (II) sulfate) on the color and fastness properties of the dyed nylon samples, was assessed. The concentration of the used mordants was 5%owf, and the dyeing experiments were conducted by applying the pre-mordanting technique. Measurement of the color strength (K/S) of the dyed fabric was done using a reflectance spectrophotometer. The dyed nylon fastness qualities and the colorimetric characteristics were then evaluated by applying the related standards. The results showed that the optimum conditions for obtaining the highest color strength were dye concentration = 50%owf, pH = 6, temperature = 100 °C, and dyeing tome = 60 min. The proposed ISO standards in relation to colorfastness displayed acceptable ratings for the color strength of dragon's blood resin dyed fabric while its treatment was done by applying bio-mordants in comparison to its metallic counterparts. Therefore, dragon's blood resin could be regarded as a promising eco-friendly natural colorant source for the purpose of sustainable nylon dyeing.