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INTRODUCTION Dye A substance that is used to change the colour of the something. Dye is a colored substance that chemically bound to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they colored. Textile dyeing Textile dyeing is a process in which colored is transferred to a textile material (like fiber and yarn) to add permanent and long lasting color. It can be done by hand or by machine. As a textile fiber has been discussed for their varied qualities and as the spinning and weaving process has been explained the qualities of durability and serviceability have been constantly stressed. When the yarn is made into fabric the interesting and intricate construction begins to add beauty of appearance as well as service ability. The various finishing process suggest additional means of enhancing the appearance of the newly formed fabric. It process to provide lasting beauty and delight to beholder by adding color to fabrics. Dyeing and printing differ in the method by which color is applied to fabrics. In the dyeing process fiber yarn or fiber is impregnated with a dye stuff .In printing a pattern or design is generally imprinted on the fabric in one or more colors by using dyes in paste form or some related means. SELECTION OF DYE: To select the proper dye for a fiber it is necessary to know which dyes have an affinity for the vegetables, animal or made fibers. In general dyes used for cotton and linen may be used for rayon’s, but other fibers requires different dyes. When a dye colour fabrics directly with one operation of impregnation, without the aid on fixing agent, the dye is said to be a direct dye for the fiber .Direct dyes are easiest to produce the simplest to apply, and the cheapest in their own limitations. One of these is the degree of color fastness. Fastness of color refers to its ability to remain unchanged. Different dyes of different colors have different degree of fastness to various conditions .For example a color that may have good fastness to laundering may have poor fastness to light. Color fastness may be affected by such factors as perspiration, dry cleaning, bleach, salt, water swimming pool additives atmospheric gases, or air pollutants. Also certain dyes may bleed or, run when wet and may cause discoloration of other fabrics. Some dyes may crock or rub off, due to the friction of water.

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Consequently, selection of the proper dye is crucial to its ultimate use .Fastness of light is important in draperies ,e.g ,as they must stand strong light daily but do not need to be washed frequently .Fastness to washing is important in dress fabrics and household linens because they must undergo to frequent washings. Therefore, both the kind of fiber be dyed and the intended use for the fabric should be considered. Once a colour has been selected, it essential that its formulation be kept consistent .Each batch that is dyed must have its dye lot number. Since variation can occur in such factor as chemical concentration, fibred structure, water content, or temperature and causes a slight change in color, each dye lot will be slightly different .Matching apparently the same colour between two different pieces may become a problem. It is therefore important to use material from the same dye lot when piecing together such items as apparel or drapery. Sometime a color may be formulated by a dyer to mach an existing colors on fabrics. When two or more types of fabrics are dyed, particularly by different dyers, the colors may appear to match in one (e.g daylight) but will not match in one light (e.g incandescent). Such as conditions is known as metamerism, or color flare. Prior testing should be made on samples on samples to avoid this difficulty. 1) SELECTION OF DYEING METHOD: Textile may be dyed at any stage of their development from fiber into fabric or certain garments by the following methods: a) Stock dyeing, in the fibre stage. b) Top dyeing, in the combed wool sliver stage. c) Yarn dyeing after the fiber has been spun into yarn. d) Piece dyeing after the yarn has been constructed into fabric. e) Solution pigmenting of dope dyeing, before a manmade fibre is extruded through the spinnerets. f) Garment dyeing after certain kinds of apparel are knitted. a) STOCK DYEING: Stock dyeing refers to dyeing a staple fiber before it is spun. In stock dyeing which is most effective and expensive method dyeing the color is well penetrated into the fibers and does not crock readily. Stock dyed fiber does not spin as readily as un dyed fiber because it loses some of its flexibility, but lubricants added in the final rinsing overcome most of this difficulty.

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Woolen are often stock dyed. Stock dyeing process mixture effects and colour blends, of which oxford suiting and tweed homespun are example. b) TOP DYEING One step nearer to the finished yarn then stock dyeing is what is called top dyeing in the worsted industry. Top is wool that has been combed to take out the short fibbers then delivered from the combs in a rope. c) YARN DYEING When dyeing is done after the fiber has been spun into yarn, it is described as yarn dyeing. d) SKEIN DYEING Yarn may be prepared in skein or hank, form and then dyed. The loose arrangement other yarn allows for excellent dye penetration. e) PACKAGE DYEING Yarn wound on spools, cones, similar unit and then dyed is referred to as package dyed yarn. f) PIECE DYEING The great bulk of dyed fabric on the market is dyed in the pieces. This method gives manufactures maximum flexibility for their inventories to meet larger small demands for a giving color as fashion require. g) UNION DYEIND This process of dyeing piece goods made up of different fibers or yarns in one color may be readily accomplished. Although different fibers may require different dyes to obtain the same color this may be done by putting the appropriate color dye that is specific to each type of fiber into one dye bath. h) BACK DYEING Long length of cloth that are to be dyed on a continues process are very often back dyed or box dyed by passing by passing the fabric in tension free rope from through the dye bath .The rope of cloth moves over a rail on to a reel which immerses it into the dye and then draws the fabric up and forward to the front of the machine. The process is repeated as long as necessary to dye the material uniformly to the desired intensity of color. Much of the original softness and

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4 fullness of the fabric is retained with back dyeing and it is therefore widely used for woolen and worsted woven goods and knitted fabrics. i) JET DYEING Fabric may be jet dyed by placing it in a heated tube or column where jets of dye solution are forced through it at pressure up to 300 pounds per jet. The dye is continuously recirculated as the cloth is moved along the tube at speeds up to 300 yards per minute. The fluid moves faster than the cloth floats through the tube without touching the walls. The method is not only fast but also very through and crease and rope marks may be avoided. j) CHIP DYEING Special dye may be added to the polymer for the production of such fibers as nylons prior to melt spinning of the chips. The dye stuffs are resistant to the reducing action of the polymer under high temperature. Such dyes will not fade crock or run. k) GARMENT DTYEING Certain kinds of non tailored apparel such as hosieries, pantyhose and sweaters can be dyed as completed garment because they are each made of a single component and will not be readily distorted. A number of garments are loosely packed into a large nylon net bag. The bags are then put into a paddle dyer which is tub with a motor driven paddle that agitates the dye bath. Garment is an economical method and is used when practical. It also reduces the risk of building an inventory that could be effect. 2) DIFFERENT EQUIPMENTS USED FOR DYEING: a) WINCH In this machine dye bath is put in a larger vat. Ropes of fabrics are sewn into a continues circle. The drums pull these ropes from the dye bath at one side and drops and they bath on the other side. The machine consumes a lot of water and can dye only at temperature below 1000c. This system is suitable for soft cotton and fully woolens. b) JET DYER Jet dyer is improved equipment used for rope dyeing.This is closed equipment through which the fabrics in rope form passes along with the dye bath. It can be pressurized and heated at 150Cfor processing. It continues less water. c) BEAM DYER

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Beam dyer is used for dyeing open width with fabric as it is not possible to dye all the fabric in rope form.Thefabric is wound evenly and loosely on a perforated beam to ensure complete and uniform penetration of dye. The equipment can be used for dyeing at standard atmospheric as well as high temperature conditions. CLASSIFICATION OF DYES:

Natural dyes Synthetic dyes

Plant dyes Animal dyes (a) Natural dye Primitive people obtained dye forms from flowers, nuts, berries and other form of vegetable and plant life, as weII as from mineral and animal sources. These sources have provided such natural dyes throughout civilization. They are no longer used in quantity by the dyeing industry, but they are still used in oriental countries to a certain extent for rug dyeing and in many parts of the world formative handicraft. The principle vegetable dyes are fustic, sumac, catechuorcutch, mudder, henna, saffron, logwood, alizarin and indigo. Animal dyes such as cochineal, sepia, lac and Tyrian purple, are obtained from species of fish and small insects. Minerals provide such dyes are blue, chrome and iron buff. 1. INDIGO Indigo dye obtained from madder plant. The plant is dug up, the roots are washed and dried and use into the powder form .This dye is dark blue in colour that was considered brilliant and exotic. This is the most ancient natural dye used by man in textiles. Indigo is about 2-3feet long plant, cultivated on thousands of acres of land in India. The whole plant is used for extraction of dye and is supplied in powder form .This give deep blue colour .This is the only natural dye which falls under vat category of dyes.

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2. LOGWOOD DYE Logwood (Haematoxylum campechianum) Log wood main use is for dyeing textile and leather but it is also used to produce the stain haematoxylin for microscopic slides. Logwood is an easy dye to use, producing violets, greys and black colour. Log wood is a spiny tropical American tree, largely found in the Yucatan Peninsula of Mexioco.The extract of this wood is purplish red dye derived from processing the darkest heartwood. Logwood extract is used to make Hematine and heamatoxilyn. 3. POMEGRANATE RIND DYE This dye is obtained from fruit of Punica granatum the colour of this dye is yellow. The main coloring agent in the pomegranate peel is granatonine.  Soak the pomegranate rind in hot water overnight.  Simmer the rind for an hour the next dat.  Let it cool down, stain the rind and save the liquid.  Add your mordant fiber to the dye pot.  Let the fiber cool in the dye bath. 4. PERSIAN BERRIES DYE Persian berries come from the Avignon buckthorn (Rhamnus saxatills) and ate also known as Avignon berries. They have been used as a natural dye for hundreds of yeare.Persion berry is a strong extract and 20 grams of persion berry extract dye 100 gram hanks of blue faced Leicester super wash wool to a very dark golden yellow and a medium yellow color respectively, depending on water quality and other factors. 5. ONION DYE An onion skin dye can be your simplest point into the world of natural dying .This dye is obtained from onion skin. The colour of this dye is yellow to copper red. Place the onion skins into a saucepan or pot and cover with water generously .Bring to the boil and simmer for approximately 30-45minutes. Once you have a lovely color in your dye pot, strain the skin off and discard them. 6. COCHINEAL DYE This dye is obtained from animal .It is a brilliant red dye produced from insect living on cactus plant (Coccus cacti). The female cochineal insect is dried in sun and then ground the dried

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7 bodies to produce a rich powdwer, when mixed with water; powder produces a deep vibrant red colour. 7. TYRIAN PURPLE DYE This dye is obtained from shell-fishes, snails etc.The colour of this dye is green, red and deep purple. It was first produced by the Phoenician city of Tyre in the Bronze age 8. LAC DYE It does not have the brilliance of cochineal red dye, like wine.Lac is the scarlet resinous secretion of a number of species of lac insects, of which the most commonly cultivated species is Kerria laca .The resinous secretion which is known as stick laccotains about 45%waxand 1%water soluble coloring material known as lac dye. 9. SAPIA DYE Sepia dye is a reddish brown colour named after the rich brown pigment derived from the ink sac of the common cuttlefish sepia. Sepia dye is mostly used in photography which changes the appearance of black and white prints to brown .Most photographic software programs and many digital cameras include a sepia tone to mimic the appearance of sepia-toned prints. Table No. 1. Some of the various natural dyes: Natural dyes Source Colour obtained Plant sources Indigo Stems and foliage of Rich blue Indigofera tinctoria Alizarin Roots of madder plant Red Logwood Vegetable dye Black Annatto Fermented fruit of Bixa Bright orange orellana Pomegranate rind Fruit of Punica granatum Yellow Myrobalam Terminalia chebula Red and brown colour Catechu/cutch Obtained from wood and Yellow-orange to brownish- pods of species of Acacia, black colour Mimosa, Terra japonica Fustic Species of sumac Yellow, brown, red hues Balsam From flower of balsamina Orange, Yellow to brown

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Harshinagar From flowers that come Yellow and orange under family Oleaceae Kamala Pods for tree belonging to Orange-red Euphorbiaceae Animal source Cochineal dye Dead bodies of female Crimson, sarlet and orange. insects, coccus cacti. Tyrian purple Shell-fishes, snails. Green, red and deep purple.

Table No. 2. Some of the various synthetic dyes: Synthetic dyes Fibers dyed Characteristics Acid dyes (anionic) e.g Wool, silk, nylon. Bright colors, poor fastness mentanil yellow, picric acid, to washing. acid magenta, acid violet. Basic Acrylics Bright colors on acrylics. dyes(cationic)e.gmalachite green A,Ethyl,violet,rhodamine Direct dyes Cellulose fibers Cheapest, easy to apply, poor fastness to washing good fastness to light Vat dyes Cotton, supports Good light and wash wear,prints,draperyfabrics fastness. Sulphur dyes Cotton, heavy work Moderate fastness to light clothes, sulphur black is and wash, sensitive to widely used. chlorine bleach. Disperse dyes Acetate and other synthetic Moderate fastness to light fibers and washing.

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Mordant dyes e.g alizarin Wool, silk, nylon, rayon. Good light and wash orange A, meta chrome fastness, dull colors. brown BR Reactive dyes Cotton, wool, silk, nylon. Excellent fastness to light, crocking dry cleaning and fume fading, affected by fluorine bleach, bright colors.

(b) SYNTHETIC DYE Synthetic dye is also known as chemical dyes. Synthetic dyes are manufactured from organic molecules. Synthetic dyes are made up of chemical compounds that can be harmful to humans, especially those who work in their production. Some of the chemicals are mercury, lead, chromium, copper, sodium chloride and benzene etc. Although synthetic dyes were first derived from coal tar in 1956. They were not developed to any great extent until world war IST when the supply of imported synthetic dye was cut off. Since then each country has built up a dye industry that is unsure passed.Inumberable dye compound made from coal tar have not supplanted natural dyes. These synthetic dyes are constantly being improved as to beauty of colour is an important factor in consumer finished good durability of colour depends on: 1. Selection of proper dye the fiber to be dyed. 2. Selection of the method of dyeing the fiber yarn or fabric. The synthetic dye is classified into several classes .The classification is based upon the particular type of chemical composition of the dye and the method of its application. 1. BASIC (CATIONIC) DYES The first coal tar dye was called basic dye. It was developed to give many bight shades for silk and wool. The chemical agents that bind the dye to a fibre, which otherwise has little or no affinity for dyes is known as mordant .Cationic dye is used for cotton, linen, nylon, polyesters and acrylics etc.They give good fastness and bright shade to acrylics for which they are principally used. Basic dyes are frequently used as an after treatment for fabric that has been previously dyed with acid colors.

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2. ACID (ANIONIC) DYES These are one of the oldest synthetic black; one of the most intense and fastest blacks available is an example of this group. Excellent browns are also available for printing. They are used primarily for cotton and can be applied with oxidizing agents and care full processing to wool, silk and acetate. 3. AZOIC DYE This is the third group of direct dyes that is further identified as naphthol and repidogen types. They are quit fast to washing and vary from poor to excellent on cotton and for special purpose on nylon and acetate. 4. DISPERSE DYE These dyes were developed originally for dyeing acetate fibers and have since found wide use in dyeing triacetate, nylon, polyester, acrylic as well as cellulose fiber. While, there are not soluble in water. 5. SULPHUR DYES Sulphur dyes first made in 1879 are used for cotton and linen. These dyes are fast to washing, light and perspiration, but they have one weakness, excessive chlorine bleaching will strip of color.Sulphar dyes are insoluble in water and must be made soluble with the aid of caustic soda and sodium sulfide. 6. VAT DYE The first synthetic vat dye was an indigo created in 1879 .Vat dye are the fastest dye for cotton, linen, and rayon. They also may be applied to wool, nylon, polyesters, and acrylics with the use of a use of a mordant. Vat dyes are not only resistant to the strong oxidizing bleaches used in commercials laundries. Table No. 3. CHEMICAL USED FOR SILK DYING . S. No. COMMONLY USED FUNCTIONS CHEMICALS 1. Urea Increase the solubility of dyes control the sublimation of high temperature 2. Lyoprint R G Control the reduction of dyes at high temperature during steaming. 3. Soda ash Control the rate of reaction between dyes

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and cellulose or in other words it is used for fixation reactive dyes. 4. Sodium bicarbonate Control the rate of reaction between dyes and cellulose or in other words it is used for fixation reactive dyes. 5. Cibaflaw pad To increase the wet ability of fabric and penetration of dyes in the fibre. 6. Anti- migrating agent Increase the viscosity of dying. To [protect the migration of dye under high temperature. 7. Anti-floming agent Used to prevent formation of foam during stirring or during dying on one bath. 8. Electrolyte Decrease solubility of dyes in liquor increases affinity between dyes and fibre under moist condition.

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Conclusion: The present scenario is focused more towards the utilization of the vast diversity of natural resources of colour pigments for their use in food materials, pharmaceuticals and textiles, in place of their synthetic counterparts. This trend is aimed at safeguarding human health as well as protecting and prolonging life on earth. Therefore, if natural dyes have to be commercialized, they need to conform to the same stringent standards of performance that are applied to synthetic dyes. It thus follows that much more research and developmental effort needs to go in this area.

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References: 1. Giridhar, K., Mahanta, J.C., Laxmanrao Deole, A. and Kantharaju, B.M. (2008). Raw silk production: Indian Silk. 2. A, Vishu. (2013). Textiles Chemistry. Abishek Publications, Chandigarh, India. 3. Basker. A.F (2010). Handbook of Textiles. Abishek Publications, Chandigarh, India. 4. Data, R. K. And Namavaty, M. (2012). Global Silk Industry. A complete Source Book. APH Publishing House. 5. Government of India, (2013), Annual Report 2012-2013, Ministry of Textiles, New Delhi. 45-52. 6. Sastry, D. U., (1984), The Cotton Mill Sector in India. Oxford University Press, New Delhi. 11-17. 7. Roy, T., (1996), Cloth and Commerce: Textiles in Colonial India, Sage Publications, New Delhi. 33-39. 8. Bhat, M. A; Aziz, A; Chanotra, S; Banday. S. A; Bujroo, Z.I and Azam, M. (2019). A Text Book on Introduction to Sericulture and Soil Science. Innovation publications. 9. Mathur, A., (2007), “Special Economic Zones in India: Analysis of the Export Performance”, Working Paper 148, Indian Council for Research on International Economic Relations, New Delhi. 22-29. 10. Rangarajan, K., (2005), “International Trade in Textiles and Clothing: Post-MFA challenges and strategic considerations for India”, Foreign Trade Review, Vol.XXXIX, Jan- March, No.4. 6.

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