Papers by Keyword: Dyeing

Abstract: Natural dye solution from longan leaves was applied to the simultaneous dyeing of silk fabric and using alum, copper sulfate, ferrous sulfate and stannous chloride as a mordanting agents. The dyeing properties and effects of simultaneous-mordanting on the hue, colour strength and colour value were revealed. The results show that The K/S values increased with an increase of metal mordant concentration. The mordant activity sequence was CuSO₄> FeSO₄> AlK(SO₄)₂ > SnCl₂. The obtained colour values show that silk fabrics dyed without mordant exhibited dark brown colour, while those mordanted with aluminum potassium sulfate (alum), stannous chloride and copper sulfate showed a variety of medium to dark brown shades. With ferrous sulfate, the colour shade was darker and duller. The colour fastness results showed good to very good level.

Abstract: The present paper deals with the application of natural dyes extracted from cassia fistula fruit or golden shower tree seed pods on nylon fabric. The dyeing properties were evaluated by measuring K/S and CIELAB values. In addition, the different fastness properties were evaluated. The effect of metal mordants at different concentration levels with respect to their colour strength was also studied. Nylon fabrics dyed with golden shower tree seed pods extract without mordant showed a light brownish-yellow shade, while those dyed with ferrous sulfate and stannous chloride brighter brownish-yellow colour. Nylon substate dyed with alum and CuSO₄ gave a duller brownish-yellow colour. The fastness properties ranged from fair to good level.

Abstract: The extractions of yellow and red pigments from safflower petals were studied. The pigment extracted was further utilized as a natural dye for silk dyeing. The safflower petals were water-extracted in order to remove the yellow pigment and the extraction of red pigment from the petals was done with alkali solution. The extracted red pigment was applied to a silk fabric by dyeing process. The effects of dye concentration and pH of dye bath were studied. The colourimetric analysis of each dyed material was done in terms of the CIELab (L*, a* and b*) and K/S values. Maximum color strength for red color was obtained at pH 4. Color fastness to washing and light was evaluated. Washing fastness was 4-5 but light fastness for red dyed silk was 1. The dyed silk did not display antimicrobial activity against the bacteria Staphylococcus aureus ATCC25923^T and Escherichia coli ATCC25922^T.

Abstract: The dyeing of cotton fabrics using Excoecaria bicolor (Excoecaria cochinchinensis Lour.) as a natural dye has been studied in both conventional and ultrasonic techniques. Excoecaria bicolor leaves were extracted by various extracting procedures, using different solvents. The extractability of dye from natural origin using power ultrasonic was also evaluated in comparison with conventional heating. The results of dye extraction indicate that power ultrasonic is rather effective than conventional heating at low temperature and short time. The color of each dyed material was investigated in terms of the CIELab (L*, a* and b*) values.

Abstract: The pad dyeing offers the most economical and convenient method of dyeing cotton fabric. The energy and water consumptions are at the lowest, thus rendering it more eco friendly. The dyeing of cotton fabric was carried out with dye extraction from the uncaria gambir by using two padding techniques, namely the pad-batch and pad-cure techniques under different conditions. The effect of dyeing method and mordant on color strength and colorimetric parameters (L*, a*, b*, and ΔE) were evaluated. The color fastness to wash, light and perspiration after dyeing the cotton fabric treated with the mordant was determined according to AATCC test method. The study showed that the color strength (K/S) of the dyed cotton fabric using pad-cure method higher than those dyed cotton fabric using pad-batch method. Meta-mordanting showed increase dye uptake and color fastness of cotton fabrics.

Abstract: Two lichens species (Parmotrema praesorediosum and Heterodermia leucomelos) were assessed for dye production using boiling water method (BWM) and ammonia fermentation method (AFM). The dyes were applied on silk fabric. Three types of mordant were used i.e. alum, iron and vinegar through meta-chrome (simultaneous) method of natural dyeing. The K/S values, colour coordinates values and colour differences (ΔE) of the dyed samples were measured. Dyeing fastness properties of the dyed silk fabrics were assessed for washing, rubbing and light. The P. praesorediosum extracts yielded beige to dull brown shades using BWM and pinkish-purple using AFM, whereas the H. leucomelos extracts produced yellowish-brown shades for both BWM and AFM on the silk substrate. Modanting seemed to be effective in increasing the K/S values of all mordanted fabrics except in the case of silk fabric dyed with P. praesorediosum extracted from AFM. Fastness ratings to washing and rubbing were all very good (5-4) for both P. praesorediosum and H. leucomelos dyed silk fabrics. The fabrics dyed with P. praesorediosum and H. leucomelos extracts produced strong and deep colours as their ΔE values were higher and increased obviously of all mordanted fabrics. It can be concluded that P. praesorediosum and H. leucomelos extracted from BWM and AFM methods can be used as an alternative dye source.

Abstract: The effect of varying gelatin concentration and temperature on the levelness of wool dyed with 2.0% o.m.f. indigo for various time periods was investigated. The degree of levelness was measured in terms of (RUI)_C values. (RUI)_C stands for corrected relative unlevelness index as reported in the work of Chong et al. [1]. The colour fastness to washing of the indigo-dyed wool using gelatin as a buffer was also determined.Gelatin, used as a buffer, potentially maintained the dyebath pH at a constant value of 10 which consequently reduced the colour variations between dyeings. The levelness of dyeing and depth of shade was found to be unaffected by varying concentrations of gelatin. While longer dyeing times resulted in higher degree of levelness and enhanced shade depths, higher dyeing temperatures did not favour the dyeing of wool with indigo, in that lower shade depths and reduced levelness were achieved. Dyeings of excellent wash fastness and dry and wet rubbing fastness were obtained.

Abstract: Raw wool fibers contain fat, suint, plant material and minerals. It is necessary to remove these from wool by scouring with a combination of detergents, wetting agents and emulsifiers before further processing. Dyeing and finishing of wool fibers is necessary for their application in apparel and also in interior, automotive, smart and technical textiles. Some of the detergents and auxiliaries used in scouring are eco-toxic and some of them are endocrine disruptors. In many countries, wool scouring and dyeing effluents cannot be discharged to watercourses without further treatment by removing color and toxic components. Wool fibers can be given chemical treatments to make them stain-resistant, flame retardant, shrink-resistant, photo-stable and resistant to insect attack. Some of the chemicals under current practice to achieve these functionalities in wool are not eco-friendly and their discharge to water course is limited to the consent limit set by environment agencies. Environmental impact assessment of raw wool production is well studied but to our knowledge no comprehensive study has been carried out around the environmental impact of chemical processing of wool. Like those of other fiber types, the wool textile industries are under intense consumer as well as stakeholder scrutiny. Accreditation schemes now exist to provide reassurance to modern consumers, who want to see that not only are the marketed products safe but also that they are processed sustainably under ethically and environmentally acceptable conditions. Several alternatives to improve the environmental credentials of various chemical processes used for wool will be discussed.

Abstract: Water silicon sol was prepared in this paper using sol-gel technology, which tetraethoxysilane (TEOS) was used as precursor. And the sol-Si/direct dye was prepared by doping dyes into sol-Si, then the sol-Si/direct dye was used to dye cotton woven fabric. The particle sizes of sol-Si and sol-Si/direct dye, the effects of sol-Si dosage, electrolyte dosage on the dyeing performance of sol-Si/direct dye were discussed. It showed that the particle sizes was really stable and under the influence of sol-Si the fastness were improved evidently, and the K/S value can be able to meet the requirements.

Abstract: In order to mitigate water scarcity and pollution as well as climate change, China government acted several environmental action plans on the industrial production in recent five years. Textile printing and dyeing enterprises are the main governance object and they carried out a series of energy/water conversation and emission/pollution reduction projects and measures. In order to evaluate the environmental performance of the projects, we compared Water footprint and Carbon footprint of unit Polyester Flannel dyeing and printing fabric in an enterprise (which conducted the environmental project from 2012 to 2013) respectively in 2012, 2013 and 2014. The results show that both Water footprint and Carbon footprint decreased significantly after the environmental project.