, English, Book, Illustrated edition: Textile preparation and dyeing / A.K. Roy "Since color makes textiles attractive, coloration or dyeing has been. Textile preparation and dyeing by Asim Kumar Roy Choudhury, , Science Publishers edition, There's no description for this book yet. Textile Preparation and Dyeing [A K Roy Choudhury] on picscobenreatttas.gq *FREE* shipping on qualifying offers. This book deals with the classical processes for.
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Shop our inventory for Textile Preparation and Dyeing by A. K. Roy Choudhury, Asim Kumar Roy Choudhury with fast free shipping on every used book we have . This book discusses in detail several emerging topics on textile dyeing. Preparation of the dye vat by reduction The vat pigments were converted to the. book addresses itself to the structure and properties of textile fibers, dyes, and this book. I especially thank Barbara Brandon for her expert preparation of the.
Thousands of dyes have been developed which have varied properties and hues. A full coverage of all such advances would require several volumes. However such an extensive coverage would be superfluous for students and technicians for whom this book is intended. This book has been written to present all the relevant information in a comprehensive yet concise manner. Contents Ch. Chemistry of textile materials Ch. Water requirements and treatments Ch. Surface active agents Ch.
Preparatory processes I cleaning Ch.
Preparatory processes II whitening Ch. Typical substantive azo dyes of the various chemical classes are now described. It is possible, however, for a dye molecule to contain two or more independent chromophoric systems electronically insulated from each other. Such dyes were first introduced by CIBA, who utilized the triazinyl ring as a chromophoric block. This ring serves as a convenient link since it can be introduced 5 by reaction of cyanuric chloride with two or three aminocontaining dyes in succession.
Substitution of the first chlorine atom takes place easily in presence of alkali at atmospheric temperature. The second chlorine atom is less easily removed, and reaction with an amino compound may require a temperature of 55o — 60oC, the optimum conditions varying with the basicity of the amine.
Replacement of the clorine atom calls for still more vigorous conditions, and a temperature of 90o — oC may be suitable; much higher temperature are needed, however, in the case of weakly basic compounds.
The progressive loss of activity at each stage enables condensation to be carried out with three different components to give a substantially homogeneous product.
The residues of three dyes Dye 1 -NH2, Dye 2 -NH2 and Dye 3 -NH2 may be linked by a series of reactions in alkaline medium, as shown: In the resulting product each dye residue contributes its own absorption characteristics; by combining yellow and blue components, green dyes can therefore be obtained that are much brighter than normal polyazo greens.
Dyes containing three inde; pendent chromophoric system is of limited interest and the third condensation is often carried out with a suitably reactive colourless compound such as aniline or phenol.
Textile preparation and dyeing
One of the aminoazo dye residues. By acetylating all of the hydroxyl group in cellulose a triacetate is obtained with a polymetric structure which may be represented thus: The triacetate is soluble in chloroform, and a fibre known as Lustron was spun from chloroform solution in early small-scale American manufacture During the First World War incompletely acetylated cellulose was produced on a large scale for use as a dope for aircraft fabric. After the war efforts to find a new use for it led to the production of cellulose acetate fibre by British Celanese Corporation.
It is spun from acetone solution. In spite of an inconveniently low melting-point acetate fibre attained great success and is still extensively used, but in recent years it has been partly superseded by other synthetic fibres. It was appreciated in the early days that the dyeing of acetae differs from that of the natural fibres and viscose in that fibre serves as a solvent for the dye. In work on dyes in the form of aqueous dispersions was carried out independently by British Celanese Corporation and British Dyestuffs Corporation.
The SRA colours of British Celanese Corporation were dispersions of aminoazo or hydroxyazo dyes obtained by means of the surface-active agent sulphated ricinoleic acid. Other dispersing agents used included alkyl sulphates, alkaryl sulphonates and fatty alcohol-ethylene oxide condensates a long alkyl chain being usually present in the molecule , and the dispersions obtained by applying them with various milling techniques were often so fine as to be easily mistaken for true solutions.
British Dyestuffs Corporation marketed dispersed aminoazo and hydroxyazo dyes in their Dispersol range, and this is still maintained by ICI formed in by a union of British dye stuffs Corporation with other firms. The Duranol range is a parallel range of dispersed dyes of the anthraquinone series.
Dyes of these types are now produced by many manufactures. Whereas the dyes were formerly supplied only as aqueous dispersionsthey are now usually marketed in the form of re-dispersible powders which yield suitable dispersions on stirring with water. Hydroxyalkylamino groups impart a small degree of watersolubility and assist dispersibility; coupling components such as N-ethyl- N- B-hydroxyethylaniline or N, N-di B-hydroxyethyl aniline aretherefore commonly used.
Many of the earlier yellow and orange dyes proved to be phototropic, but it was found that this groublesome characteristic can be largely avoided by introducing nitro or other negative groups into the dye molecule; these substituents restrain trans cis isomerizatrion.
Since dye molecules must be fairly small in order that they dissolve readily in the fibre monoazo dyes are commonly used, but a few disazo dyes are included in commercial ranges. Blacks are obtained by diazotising aminoazo dyes on the fibre and developing with a solution of 3-hydroxy- 2-naphthoic acid.
In a range of water-soluble dyes for acetate was marketed by ICI under the name Solacet. Their solubility was due to the presence of a sulphuric ester group -- OSO3Na , usually introduced by sulphation of a B-hydroxyethlamino group, which did not seriously impair affinity for the fibre. In consequence of the of the development of dispersed dyes with improved dyeing and fastness properties the Solacet range has now been superseded.
Many dyes developed for acetate have now been applied to the newer synthetic fibres, and the manufactured ranges have been extended specially for these outlets. Disperse dyes for fibres other than acetate are described later. Examples of azo disperse dyes applied to acetate are shown in Table 4. Cellulose triacetate was manufactured in the United States during the period , but the process was unsatisfactory because the only suitable solvent then 8 commercially available was chloroform, and this was both toxic and expensive.
Methylene dichloride is a suitable solvent of low toxicity, and it became available fairly cheaply about , but by the eat time secondary acetate was fully established. It has good shrink- and crease- resistance, is quickdrying, shows good fastness to wet treatments and can be heat-set without loss of lustre. As it has a higher melting point the hazards associated with the ironing of fabrics of secondary acetate are largely avoided. Because of its hydrophobic character triacetate is less easily dyed than acetate, but suitable dyes can be selected from existing ranges of disperse dyes.
Whereas acetate is dyed at 75o— 80oC, triacetate requires a temperature at or near the boil. If the fabric is to be heat-set for pleats the dyes used must be stable at oC.
Home Economics: Textiles, Fiber Science, Dyeing
Since many suitable dyes are available, commercial ranges are usually selected from products already manufactured for other purposes, and apart from the reactive dyes discussed later new structures have not been required. It has proved very difficult to manufacture nylon with uniform dyeing properties, and for this reason dyes with good leveling properties are necessary.
In this respect disperse dyes have a great advantage in that they conceal fibre irregularities. For high wet-fastness acid dyes are preferred, but very careful application is necessary in order to secure level dying. These dyes often show better wet-fastness properties on nylon than on wool because of the hydrophobic character of the former. Fastness to light, however, is often slightly lower on nylon than on wool.
The affinity of acid dyes for Nylon 6 is higher than that for other types because polycaprolactam fibres contain a higher proportion of free amino groups Ranges of acid dyes for nylon are classified by the makiers so that users may select dyes with good leveling or good wet-fastness properties according to their requirements, there are also ranges with intermediate properties and others specially designed for fabric printing. In the course of the exploratory work that led to the development of nylon W.
Carothers examined aliphatic polyesters but abandoned them in favour of the more promising polyamides. Subsequently, however, the late J. Whinfield and J. They extended the work to aromatic compounds and obtained a polymer with excellent fibre-forming properties from terephthalic acid and ethyleneglycol.
This has the structure 3. Development and production of the fibre were carried out by ICI, and this fibre is now manufactured under various names on a very large scale in many parts of the world.
Dimethyl terephthalate is now commonly used in place of the free acid so that the terminal carboxlic acid group is esterified.
Since n has a value of about 80 the properties of the fibre are not greatly affected. The ester is preferred as starting material because it is more easily purified, and purity is essential in the manufacture of high polymers. It is largely used for manufacture of net curtains, in blends with wool for suitings and other outerwer,k and for many industrial purposes. Certain disperse dyes can be applied, but under normal conditions adsorption is slow and only pale shades are obtained.
Much better penetration is obtained by dyeing at about 12Oc under pressure, and the special dyeing machinery required is now in general use. Since diffusion is slow in conditions of normal use, dyeings obtained in this way have good wet-fastness properties. Suitable dyes must be selected for this process since not all will withstand the high temperature without change of shade.
Their presence greatly facilitates the dyeing process, but the mode of action is not fully understood. This process enables dyeing to be carried out in standard machines, but it is somewhat expensive and has disadvantages in that the carriers are often difficult to remove completely; their presence may cause a noticeable odour and sometimes impairment of light-fastness.
Polyester fibres can be dyed by the Thermosol process DuPont , which consists in padding with disperse dye and a thickening agent, then drying and heating at o — oC for about one minute. Under such conditions the dye is absorbed rapidly; after scouring to remove loose colour the dyed material is finished in the usual way.
Its homologure polypropylene exists in various forms according to the disposition of the substituent methyl groups; the isotactic polymers, in which these groups are all attached on the same side of the main carbon chain, can be spun and drawn into fibres.
Catalysts promoting formation of isolactic polymers were discovered by Zeigler, and the process was further developed by Natta and others Polyproplene fibres and hydrophobic and resist chemical attack, but they are not readily dyed.It is possible, however, for a dye molecule to contain two or more independent chromophoric systems electronically insulated from each other.
In work on dyes in the form of aqueous dispersions was carried out independently by British Celanese Corporation and British Dyestuffs Corporation. These steps are important for maintaining consistent product quality. Subjects Textile finishing. Can you add one?
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