According to the literature, it is possible to replace synthetic dyes with more echo-friendly natural dyes. One of the popular natural dyes in Iran is madder. This paper reports the effect of age and type of madder in natural dyeing process for better color behavior prediction. Effects of 4 different types of madder along with the role of the concentration and pH of dye bath are investigated. The amount of dye absorption is also evaluated by calculation of K/S value in the wavelength of minimum reflection. Samples are treated by using the classical after treatment process for natural dyes and the effect of after treatment on light and washing fastnesses of samples are reported. The CIELAB colorimetric specifications of samples are measured under D65 illuminant and 1964 standard observer. The light and washing fastnesses of dyed samples are also reported. Finally, the chemical structures of employed madders are studied by FTIR technique.

Dyes can be derived from nature through various sources such as plants, flowers, seeds, barks, and roots. In this work, wool fabrics dyed with natural dyes extracted from the tea. Three different mordants were used in the experiments, potassium dichromate, copper sulphate and aluminum sulphate. The dyeing was carried out with mordant by using pre-mordanting method. Three properties of the finished samples such as wash fastness, rubbing fastness and dye color were evaluated. The latter was evaluated by using spectrophotometer color matching system. Various colors have been produced by using different mordants. The wash and rubbing fastness of the samples dyed with aqueous extract of tea were found to be good to excellent.

An ecological approach has been obtained by using natural dyes and mordant for dyeing process. Fabrics were dyed using myrobalan extract as natural mordants and green dye. A red color was obtained by using theses mordants. The color of dyed fabrics was investigated in CIELab (L*, a* and b*) and K/S values. Finally, all dyed fabrics were tested for wash and light fastness properties as per ISO standard test methods. The results of using biomordants for fabrics dyeing were comparable with that of metallic mordants in terms of color strength and fastness properties. Myrobalan extract as biomordant produced red color with medium fastness properties and thus offer full potential to replace metal salts in dyeing process. Prog. Color Colorants Coat. 11 (2018), 79-83© Institute for Color Science and Technology.

One of the main and essential problems in the dyeing units of the textile industry is the volume of pollutants produced, which has endangered the health of the environment through ground water pollution. Despite not causing respiratory and skin allergies and good compatibility with humans and nature, natural dyes can cause environmental problems by creating effluents. The resulting dyeing effluents often contain metal ions and colored compounds that can be harmful to the health of organisms and cause various diseases. Usually, different natural dyes such as madder, weld, walnut shell, and cochineal are used with different concentrations during the dyeing process. Besides, along with pre, simultaneous and post-mordanting methods, various mordants such as aluminum sulfate, copper sulfate, and potassium dichromate are applied. In this research, a review study has been conducted on the effect of using these dyes, types of applied mordant, and different dyeing methods on parameters such as BOD, COD, and TDS of resulted effluents.

Today, natural colorants are emerging globally due to the fact that they are safer and more environmentally-friendly. Natural dyes have been employed in dyeing Persian carpet piles for many years. In this study, the dried Achillea was used for dyeing wool yarns. The Iranian wool yarn was scoured, mordanted using Cu, Sn, Al salts and then dyed with different amounts of dried Achillea powder. Taguchi statistical method was employed to find theeffective factors and results of the planned experiments, in order to optimize the dyeing factors. A L9 orthogonal array (four factors in three levels) was employed to evaluate the effects of different parameters in dyeing process. The colorimetric properties of the dyed yarns were evaluated in CIELAB system. Achillea found to have good agronomic potential as a natural dye in Iran. Dyeing with Achillea in conjunction with metal mordants showed enhancement in its fastness properties. Therefore it shows commercial capability for dyeing of wool yarns used as Persian carpet piles.

In this study, dyeing of two regenerated polyester fibers, poly-trimethylene terephthalate (PTT) and poly-lactic acid (PLA), with natural dyes were compared with that of poly-ethylene terephthalate (PET) fiber. Lac was used as the primary natural colorant while Catechu was chosen as a natural color that can also act as a biomordant. The effects of temperature, initial pH of dye bath and dyeing time on color strength of the fibers were examined with Lac and Lac-Catechu combination. The results indicated the regenerated polyester fibers to have more number of functional groups and less compact structure than PET, favoring dyeing under milder conditions. PTT exhibited higher color uptake than the other fibers. Also, with Lac and Catechu in the same dye bath, the color strength was found to increase for all fibers, indicating that Catechu acted as a biomordant. Response Surface Methodology (RSM) based on 23-Central Composite Design (CCD) was used for optimization of dyeing of PTT with Lac-Catechu combination. The optimal values for temperature, initial pH and dyeing time were found to be 127OC, 6 and 26 min, respectively. The quadratic regression model developed was found to be statistically significant using ANOVA, with R2-value and adjusted R2-value of 0. 9708 and 0. 9271 respectively.

In this research, the dyeing of nylon fabrics with sumac as a natural dye was investigated and the effect of keratin treatment on the dyeing properties was studied. For this purpose, first keratin was extracted from chicken feathers by the reduction hydrolysis method, and then surface modification of nylon fabric with the extracted keratin was performed via the exhaustion method. The chemical structure of the treated fabrics was evaluated by FTIR and the results proved the successful keratin treatment on the surface of the fabrics. The obtained results showed high dye absorption of keratin-treated fabric in comparison with mordant-treated and untreated fabrics. Thus, keratin could be used for enhancing the absorption of natural dyes. Colorfastness properties of the dyed fabrics with sumac were evaluated and high washing and rubbing fastness were attained. Finally, the antibacterial properties of the dyed fabrics against both gram-positive and gram-negative bacteria were performed and the results showed the antibacterial activity of sumac.

nowadays, there is a great tendency for eco-dyeing and finishing of textiles with natural products. several natural dyes have been used for dyeing of protein fibers but a low number have the ability to dye cotton fiber because of low affinity of cellulose to the natural dyes. In this study madder and weld natural colorants were used to dye cotton fabric premordanted with three metallic salts including alum, ferrous sulfate, and copper sulfate. The effects of the concentration of mordant, dyeing temperature, dyeing time and amount of electrolyte on the color strength of dyed samples were investigated. Also, an eco-friendly process, low temperature plasma treatment was employed as a pretreatment to improve the dye exhaustion into the cotton fibers. The fastness properties of cotton samples dyed under different conditions were evaluated and the optimum amount of each variable for obtaining the highest values of color strength and fastness properties in the dyeing of cotton with madder and weld natural dyes was specified. Prog. Color Colorants Coat. 12 (2019), 191-201© Institute for Color Science and Technology.

an ecological approach has been obtained by using natural dyes and mordants for dyeing process. Silk fabrics were dyed using natural mordants including powder of sour pomegranate, sweet pomegranate and their mixture. A beautiful red color was obtained using theses mordants. The color of dyed silk fabrics was investigated in CIELab (L*, a* and b*) and K/S values. Finally, all dyed fabrics were tested for wash and light fastness properties as per ISO standard test methods. The results of using biomordants for silk dyeing were comparable with that of metallic mordants in terms of color strength and fastness properties. Pomegranate extract as biomordant produced red color with medium fastness properties and thus offer full potential to replace metal salts in silk dyeing process. Prog. Color Colorants Coat. 10 (2017), 129-133© Institute for Color Science and Technology.