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Chiquita Palafox
Textile Dyeing Edited by Peter J. Hauser Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright 2011 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. As for readers, this license allows users to download, copy and build upon published chapters even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Silvia Vlase Technical Editor Teodora Smiljanic Cover Designer InTech Design Team Image Copyright Benjamin Mercer, 2011. Used under license from Shutterstock.com First published November, 2011 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from [email protected] Textile Dyeing, Edited by Peter J. Hauser p. cm. ISBN 978-953-307-565-5
Nearly all textile materials are colored after fabrication and before final finishing. The coloration of fibers and fabrics through dyeing is an integral part of textile manufacturing. This book discusses in detail several emerging topics on textile dyeing.
The pretreatment of textiles prior to dyeing is addressed by several authors. Menezes and Choudhari present chemical alternatives to traditional pretreatment, while Tavcer discusses enzyme pretreatment procedures. Bendak and Raslan review pretreatment methods of protein and synthetic fibers, and Bhatti et al. introduce the concept of radiation induced pretreatment. Control of the dyeing process is discussed by Gnay and enhancing the dyeability of fibers is reviewed by Gashti et al. Details for dyeing specific fiber types are given by Gupta et al (polypropylene), Suesat and Suwanruji (polylactic acid), and Gimnez-Martn et al (acrylic). Individual dyestuff classes are addressed by Koh (disperse dyes), Rippon et al (vat dyes). The use of cyclodextrins as dye leveling agents is reviewed by Voncina while Durasevic et al. suggest that photochromic dyes can function as useful sensors. The interaction of plasma with textile material prior to dyeing is well represented with chapters by Durasevic et al, Souto et al, Deshmukh and Bhat, and Mokbul and Dirk.
Love for colours is a natural instinct and every individual has his own choice and liking for colour. The icy appearance of Hamaliyan ranges or lush green forests or fields of agriculture or trees laden with colorful fruits or butterflies moving from flower to flower presents the beauty of nature, generation after generations are being attracted. The choice of beautiful fascinating colours reflects the aesthetic sense of humans that varies. Colour is visual perceptual property corresponding in humans to the categories called red, yellow, blue and others. It is a sensation that arises from the activity of retina of the eye and its attached nervous mechanism, and results in a specific response to the radiate energy of certain wavelength and intensity. Thus it is a quality of an object with respect to light (Mizzarini et al., 2002).Colorants may be either pigment or a dye which are characterized by their ability to absorb or emit light in the visible range 400-700nm.They may be organic or inorganic depending upon their structure and method of production. Dyes are the coloured substances which are capable of imparting their colours to the matrix which may be fiber, paper or any object. They must have fixing tendency on a fabric that is impregnated with their solution and the coloured fixed dyes must be fast to light as well as resistant to action of water, dilute acids, alkalies, various organic solvents used in dry cleaning, soap solutions, detergent, etc ( Shukla, 1992 ) . A pigment generally is a substance which is insoluble in the medium in contrast to dye in which it is applied and has to be attached to a substrate by additional compounds e.g. polymer in paints and plastics (Taylor and Nonfiction, 2006) A compound looks coloured because it has absorbed certain electromagnetic radiation from the visible region. The moieties, present in colouring substance, responsible for the absorption of electromagnetic radiation and reflect in the visible region are called chromophores (Younas, 2006).Ultraviolet radiation constitutes to 5% of the total incident sunlight on earth surface (visible light 50% and IR radiation 45%). Even though, its proportion is quite less, it has the highest quantum energy compared to other radiations. Light is electromagnetic in nature. Within the electromagnetic spectrum, human eye captures visible light in the range between about 380 nm and 700 nm (Mizzarini et al., 2002). Dyes absorb electromagnetic radiation of varying wavelength in the visible range of
All colourants obtained from animals, plants and minerals without any chemical processing are called natural dyes.e.g.Alizarin a pigment extracted from madder, tyrian purple from snail and ochre which is a mineral of Fe2O3 (Gulrajani, 1992). Natural dyes may be vat dyes, substantive or mordant dyes as they require the inclusions of one or more metallic salts of tin, chromium, iron, copper, aluminum and other for ensuring reasonable fastness of the colours to sun light and washing. The natural dyes have several advantages such as: these dyes need no special care , wonderful and rich in tones , act as health cure, have no disposal problems, have no carcinogenic effect ,easily biodegradable, require simple dye house to apply on matrix and mild reactions conditions are involved in their extraction and application (Sachan and Kapoor,2004).There are some limitations of natural dyes which includes, lesser availability of colours, poor colour yield, complex dyeing processing, poor fastness properties and difficulty in blending dyes (Pan et al., 2003). Table 1 given below, shows the classification of dyes based upon both colours and structures.
Colours Chemical Classification Common NamesYellow and Brown Flavone Dyes Quercitron, TesuYellow Iso-quinoline Dyes BarberryOrange- Yellow Chromene Dyes KamalaBrown Naphthoquinone Dyes Henna , AlkanetBlack Benzophyrone Dyes Cochineal , MadderBlue Indigoid Dyes LogwoodRed Anthraquinone Dyes IndigoNeutrals Tannins Pomegranate, Eucalyptus
Reactive dyes: Reactive dyes are the best choice and other cellulose fiber at home or in the art studio. Fixation of dye occur onto the fiber under alkaline conditions by forming a covalent bond between reactive group of dye molecule and OH, NH, SH etc groups present in the fibers (Cotton , wool , silk , nylon etc). Mordant dyes: Applied in conjunction with chelating salts of Al, Cr and Fe. Metallic salts or lake formed directly on the fiber by the use Al, Cr or Fe salts which cause precipitation in situ. Sulfur dyes: These dyes are used for dyeing cotton and rayon. The application of this dye requires careful process due to its water-soluble reduced form and insoluble oxidized form. These dyes are fast to washing but poorly fast to chlorine and give dark and dull colors. Vat dyes: These dyes are insoluble in water and cannot be directly applied to textiles. These dyes require oxidation as well as reduction step for its application onto matrix. Acetate rayon dyes: Developed for cellulose acetate and some synthetic fibers (Kim et al., 2005; Shenai, 1992). Dyes are synthesized in a reactor, filtered, dried, and blended with other additives to produce the final product. The synthesis step involves reactions such as sulfonation, halogenation, amination, diazotization, and coupling, followed by separation processes that may include distillation, precipitation, and crystallization. In general, organic compounds such as naphthalene are reacted with an acid or an alkali along with an intermediate (a nitrating or a sulfonation compound) and a solvent to form a dye mixture. The dye is then separated from the mixture and purified. On completion of the manufacture of actual colour, finishing operations, including drying, grinding, and standardization, are performed. These steps are important for maintaining consistent product quality.
Cotton the most abundant of all naturally occurring substrates and is widely used. For the fabric strength, absorbency quality, capacity to be washed and dyed, cotton has become the principal clothing fabric of the world. The materials characteristically exhibit excellent physical and chemical properties in terms of water absorbency, dye ability and stability and can not be entirely substituted by artificial polymer fibers (Jun et al., 2001). The cellulose consists of glucose units linked together through oxygen atoms, 30 to several hundred chains from micro fibrils (Foldvary et al., 2003). By dry weight 94% of cotton is made up of cellulose. The remaining constituents include 1.3% protein, 1.2% pectic substances, 0.6% waxes, 1.2% ash, and 4% of other components. Of three hydroxyl groups on the cellulose ring, two are secondary, and one is primary. Most of the reactions with cellulose occur at the primary hydroxyl groups.