China
Africa
Explore chapters and articles related to this topic
Direct, Discharge and Resist Styles of Printing
Published in Asim Kumar Roy Choudhury, Principles of Textile Printing, 2023
Vat dyes are characterized by excellent all-around fastness and full range of shades with moderate to high brightness. But these dyes are generally costly. Starch-tragacanth mixture thickener is found to be most suitable to give maximum color yield and brightness in printing with vat dyes. For sharp outline and level prints, British gum is recommended. British gum is a modified starch powder mainly used in the textile industry for printing applications. It has good adhesiveness and shine with fast drying properties. British gums are made by heating the starch at a relatively high temperature in the presence of an alkali. British gums have a darker color than do white dextrin. Yellow dextrin is known as a highly modified product, made by heating the starch to relatively high temperatures in the presence of an acid.
Fabric Dyeing and Printing
Published in Tom Cassidy, Parikshit Goswami, Textile and Clothing Design Technology, 2017
In spite of the highest all-round fastness, vat dyes are not much used for fabric dyeing due to high cost and poor leveling properties. The vat dyes are first passed with little water and reduced with sodium dithionite or Na2S2O4 (sodium hydrosulfite), commonly known as hydros and caustic soda. The fabric is first run in blank dyebath having hydros and caustic soda and the concentrated reduced dye is slowly added in the bath. The concentrations of hydros and caustic soda, and temperature of the dyebath should be strictly maintained. The presence of the chemicals should be constantly monitored and added as and when required. Excess chemicals may cause overreduction. Closed dyebath is preferred to prevent premature oxidation. After dyeing, the dyes in the fabric are to be oxidized in air or with oxidizing agent followed by washing and soaping.
Dyeing and Recent Developments
Published in Asis Patnaik, Sweta Patnaik, Fibres to Smart Textiles, 2019
Prithwiraj Mal, Debojyoti Ganguly
Vat dyes are among the oldest natural colouring matter used for textile materials. Indigo is one of the natural vat dyes used in India since prehistoric time. Vat dyes (parent vat dye) are insoluble in water but become soluble after treatment with reducing agent and alkali. Further to the chemical reduction process, these dyes can also be reduced by fermentation process. Vat dyes in the soluble form are known as ‘leuco vat dye’, which have good affinity towards textile materials. After completion of dyeing of textile with leuco form of vat dye, it is re-oxidized in presence of aerial oxygen or other oxidizing agents into the insoluble parent vat dye. Dyeing with vat dyes involve the following four different steps (Trotman 1985; Roy Choudhury 2011). Vatting – Dissolution of vat dyes takes place under alkaline reducing condition with the help of sodium hydrosulphite and sodium hydroxide.Dyeing – Material is impregnated into dissolved vat dyes to absorb.Oxidation – The reduced absorbed dyes are oxidized in the presence of aerial oxygen or some oxidizing agents like hydrogen peroxide and convert it into its insoluble state.After treatment – The dyed fabric is washed thoroughly in the presence of detergent and soda ash to remove any unfixed dyes from the fabric surface.
Study on the factors influencing the dyeing performance of cotton fabric with vat dyes based on principal component analysis
Published in The Journal of The Textile Institute, 2021
Yu-wen Wang, Qing-zhu Yi, Yi Ding, Feng Ji, Ni Wang
In recent years, many dyeing enterprises began to use vat dyes to dye cotton fabrics with the increasing demands of consumers on the color fastness of textiles. At the same time, the vat dye with good color fastness is selected to avoid the influence of fabric fading on the experimental results. Vat dye is a kind of dyestuff with excellent properties. It has complete chromatogram, bright color, excellent dyeing reproducibility, high fastness to both soaping and sunlight. In addition to being suitable for cotton fabrics, it is also suitable for one bath one color dyeing of blended fabrics such as polyester/cotton and brocade/cotton. These dyed fabrics can be used to make military uniforms and battle suits, with excellent various fastness and infrared resistance and other special properties. Vat dye has great potential value in military textiles. Therefore, eight kinds of cotton fabrics with different fabric structures were selected and pad dyed with vat dyes to measure the color and analyze whether it affected the dyeing effect or not. Then, the comprehensive properties of fabrics were analyzed by principal component analysis method to get the main factors according to their factor weights, at the same time, the mathematical regression model between the comprehensive values of fabric properties and the dyeing effect was established.
Vat dyeing of lyocell fabric with high temperature dyeing technique
Published in The Journal of The Textile Institute, 2022
Rashid Hussain Memon, Uzma Syed, Khanji Harijan, Faraz Khan Mahar, Aijaz Ahmed Babar, Sadam Hussain, Bilquees Hussain, Zeeshan Khatri
After the dyeing, the effluent quality was analyzed by considering total dissolved solids (TDS), total suspended solids (TSS), pH, and electrical conductivity (EC) of the drawn effluent. Results revealed that the dyeing of lyocell fabric with dyes offered lower effluent load as compared to dyeing of cotton fabric with vat dyes. The overall results were further tabulated in Table 4. The environmental impact caused by Vat dye was also observed. The effluent results of samples dyed with vat dyes showed certain decrement in TDS (ca. 48%), and TSS (ca. 34%) and our findings also suggest that lyocell fabric can be used as alternative of cellulose fabric as it displays relatively higher color yield and lower effluent problems.
Biodegradation and detoxification of dyes and industrial effluents by Ganoderma weberianum B-18 immobilized in a lab-scale packed-bed bioreactor
Published in Bioremediation Journal, 2018
Giselle Torres-Farradá, Ana M. Manzano, Miguel Ramos-Leal, Osmel Domínguez, María Isabel Sánchez, Jaco Vangronsveld, Gilda Guerra
The results of decolorization activities of this fungus in SSF were summarized in Table 1. G. weberianum B-18 was able to decolorize, partially or completely, all nine synthetic dyes after 15 days of cultivation, with values of decolorization higher than 75%. However, the vat dye Bezanthrene orange GR was more resistant to the biodegradation with 55.01%.