TEXTILE PROCESSING

PREPARED BY SHEEBA.C ASSISTANT PROFESSOR , DEPARTMENT OF COSTUME DESIGN AND FASHION TEXTILE FINISHES

Textile finishes refer to a finishing treatment given to a fiber, yarn, fabric either before or after fabrication to improve its physical appearance, functionally, hand , drape, and easy care features. APPLICATION OF TEXTILE FINISHES

1.Water bath finish ▪ It is one of the main application method for year. ▪ Inexpensive, and readily available solvent. ▪ In this method , the chemical was dissolved in water and applied on to the fabric by immersion and squeezing out the extra. APPLICATION OF FINISHES

2.Foam finishes ▪ Foam finishing saves water and energy. ▪ This method utilize foam instead of a liquid to apply the finish. ▪ Foam is made up of a mixture of air and liquid and therefore a small amount of liquid is used and absorbed by the fabric. APPLICATION OF FINISHES

3.Solvent finish ▪ Solvent finishing was developed to reduce water pollution and lower energy costs. ▪ In this process , the finishing chemical is mixed in a solvent.

These finishes can be applied in open width or rope form. CLASSIFICATION OF FINISHES

Finishes can be classified as based on, • Types of finish: preparatory finishes, aesthetic finishes, and functional finishes • Process of finishing : Chemical finishes and mechanical finishes • Durability of finishes : Permanent finishes, durable finishes, semi-durable finishes and temporary finishes 1.PREPARATORY FINISHES

The preparatory finishes are applied to fabrics to make them suitable for dyeing, printing, and further finishing processes. ▪ Desizing: Desizing is a process of removal of sizes starches and other substances applied to the yarns before the process of weaving. PREPARATORY FINISHES

▪ Singing The process of singeing involves the burning of fiber ends projecting from the fabric by using one or more gas flames. This process helps in making the fabric smoother and finer. PREPARATORY FINISHES

▪ Souring Souring is carried out to remove natural or applied impurities from the fabric before further finishing operations and dyeing. The impurities could be in the form of oils, starches, natural waxes, soil, and color tints. PREPARATORY FINISHES

▪ Bleaching Bleaching is carried out to remove the natural color and hydrophobic impurities of the fiber and make it white in color. It is done on fibers, yarns or fabrics. Most bleaches, such as hydrogen peroxide are oxidizing agents and the action is carried out by the active oxygen present in them. PREPARATORY FINISHES

▪ Mercerizing: Cellulosic yarns or fabrics undergo the mercerization treatment to increase their strength, luster, softness and affinity for dyes and water- borne finishes due to swelling of the fibers. PREPARATORY FINISHES

▪ Sizing Sizing finish provides stiffness, weight and body to the fabric. Water-soluble sizing is temporary, while rein-based sizing is permanent. During the process, the fabric is immersed in a mixture of waxes, oils, glycerin and softeners in adequate quantity. Talc, clay or chalk is used to add weight to the fabric. PREPARATORY FINISHES

Calendering involves a pressing process in which a fabric is passed between heavy rollers to make it smooth and glossy, it is a mechanical finish and the process is not permanent and needs to be repeated after each laundering. 2.AESTHETIC FINISHES

Aesthetic Finishes are applied to fabrics to change their appearance and hand. They create and applied design on the already constructed fabric and are therefore quicker and less expensive to produce than fabrics with structural designs, that is, designs incorporated during fabric construction , such as dobby and jacquard patterns, in woven's and knits. AESTHETIC FINISHES

▪ Luster Finishes Luster finishes are applied to improve the fabric luster. They act by changing the light reflectance of a fabric. These finishes are applied by calendering, in which the fabric passes between two cylinders, which exert pressure to apply the finish. AESTHETIC FINISHES

▪ Moireing The moire effect provides a wood grain or water marked appearance. ▪ Schreinerizing. Schreinerizing provides a sharp line appearance. This process is carried out with a metal roller engraved with very fine 200-500 diagonal lines per inch of the roller. 3.FUNCTIONAL FINISHES

Functional finishes given to fabrics to improve their performance in terms of stability , shape, appearance, comfort, resistance to insects and microbes, and safety. a)Comfort Related Finishes

Comfort related finishes are given to fabrics to them comfortable to wear. ▪ Water-repellent Finishes : Water-repelling fabrics are resistant to wetting but tend to get wet in excessive water, water repellency is dependent on surface tension and fabric permeability and therefore can be controlled by a combination of right fabric construction and finishing . a)Comfort Related Finishes

▪ Water-repellent Finishes Water-repelling fabrics need to have a very high warp count and should be made of regular yarns. The most common water-repelling chemicals are silicones, as they are durable when combined with durable press finished. These also give the fabric good drape,soft hand and stain resistance. Comfort Related Finishes

▪ Anti- static Finishes Static build up refers to the problem of garments clinging on to the body or to other fabrics. Static build-up also creates problems during production as fabrics cling to the machinery and attract dust and dirt. Anti-static finishes in the form of ammonium compounds are applied to reduce the static build-up on fabrics. These finishes act by improving surface conductivity so that excess electrons move to the atmosphere or ground. b)Safety-Related Finishes

Safety-related finishes are applied on fabrics to make the wearer safe as per their usage. There are various types of Safety-related finishes. ▪ Flame –Retarding Finishes Flame-related finishes act by either blocking the flame’s access to fuel and hindering flame propagation or emitting a flame extinguishing gas. They also act by modifying the solids so that the end-products of combustion are not volatile or require excess heat to continue the fire. c)Biological Control Finishes

A large number of insects can damage textiles, especially when the fabric is stored in dump and warm conditions. Therefore, the fabrics should always be stored in dry conditions after cleaning. For extra protection, some finishes can be applied to the fabrics. Biological Control Finishes

▪ Anti-Mildew Finishes Both cellulosic and protein fibres are damaged by moulds and mildew. It is best to prevent mildew growth by keeping textiles clean and dry and by regularly sunning and airing them. Electric lights and dehumidifiers can be used in dark and humid places. The finishes in the form of salicylanilide, also known as fungicides are applied to prevent mildew growth. Biological Control Finishes

▪ Anti-Moth Finishes Insects, such as silverfish, crickets and cockroaches, damage textiles, especially the textiles that are soiled. Moths and carpet beetles damage protein fibers. The problem aggravates in heat and moisture. ▪ Insect control finishes, knows as fumigants and insecticides can be used to protect the fabrics. ▪ Other method of insects control storing fabrics in a cold place. Biological Control Finishes

Anti-Bacterial Finishes Anti-Bacterial finishes act by inhibiting the growth of bacteria and other odor-causing germs, preventing damage due to sweat, controlling spread of disease, and reducing infection risk after injury. These finishes are also known as antibacterial , antiseptic and germicidal. These finishes are used in hospital linen; contract carpeting, and skin contact clothing. Biological Control Finishes

▪ Anti-Bacterial Finishes The most widely used finish these days is irradiation treatment or sterilization, also known as electron beam sterilization. This treatment is cheaper, simpler, safer and is used for medical products, such as sutures and bandages. The beam can penetrate thermoplastic and foil packaging and therefore the goods can even be treated in the packed state. This process maintains the sterile environment until the package is opened. DYEING

Definition: Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. TEXTILE DYEING

Dye: A dye can generally be described as a colored substance that has an affinity to the substrate to which it is being applied. The dye is usually used as an aqueous solution and may require a mordant to improve the fastness of the dye on the fiber. Pigment: Pigments are the special type of dyeing or printing materials for wet processing technology. Generally pigment is use for printing. Pigments can be define as a water insoluble coloring material mostly mineral origin have been used for coloration of metal, wood, stone and textile materials Difference between Printing and Dyeing

Dyeing has no According to localized application. the design printing has localized application of dyes or pigments on the fabric Color is Color is applied in form of solution. applied in form of thick paste. In this In printing process fabric, yarn and fibers are dyed. only fabric are print. liquor ratio is higher. Less liquor ratio here than dyeing application. Thickener is not used here. Thickener is widely used here. Steaming is Steaming is used in the printed fabric for not required on dyed material. fixation. Here, color penetrates throughout the Here, color is applied only in the fabric fabric. surface. less expensive. More expensive. Classification of dye DYES

Acid or Anionic Dyes Acid or Anionic dyes have a complete color range and can be used on protein fibers and man- made fibers, such as polyester, modified acrylic and modified rayon. The dyes produce bright colors but have poor fastness to washing and therefore fabrics need to be dry-cleaned. DYES

Azoic Dyes Azoic dyes are applied in cold bath with ice, as this helps lower the dye-bath temperature for efficient dyeing. They are also known as ice colors. The dyes have a complete color of bright shades in yellows,reds and blacks. The dyes are cheap and are mainly used for cottons along with limited use on acetate and nylon. DYES

Basic or Cationic Dyes The first synthetic dyes produced belonged to the class of Basic or Cationic dyes. It also have a complete color range with bright colors, but have limited use these days. It can be used to dye cottons with the help of mordants, while other fibers, such as wool, silk, nylon, acrylic, and polyester, can be dyed without mordanting. Basic days are mainly used on acrylics and for direct printing on acetate and discharge printing on cottons. DYES

Direct Dyes(developed) Direct (developed) dyes are developed in the fiber with the help of copper salts. It also have a complete color range through the colors are not as bright as in the case of acid or basic dyes. They are used to dye cellulosic fibers, but some can dye wool, silk, and nylon fibres. DYES

Disperse Dyes Disperse class of dyes was developed for acetates but is presently used for all man-made fibers. Disperse dye is insoluble in water, the dye particles disperse in water so as to dissolve in fibers. Shade range is good. The dye fastness to light is fair to excellent while having fair to good wash fastness. Fastness to perspiration, rubbing, and sea water is good, but it can stain wool badly. DYES

Reactive Dyes Reactive dyes are available in several varieties, such as hot and cold. These dyes form chemical combinations with the fiber and produce the brightest shade on cottons. The dye provides good all-around fastness and is used for dyeing at the fiber stage, yarn stage, fabric stage and is also used for printing. DYES

Reactive Dyes Some reactive dyes can be used for wool, silk nylons, acrylics, and blends. These dyes have good light, wash and dry- cleaning fastness. They also have good resistance to bleeding perspiration, rubbing, and sea water. DYES

Sulfur Dyes Sulfur dyes are generally insoluble in water. The colors are not bright and shade range is also incomplete. The dye can be applied at the fiber, yarn of fabric stage. It Is used for both heavy woven and cotton knits, and jute and linen. It is not used much for printing. DYES

Vat Dyes Vat Dyes are insoluble in water and require reduction for their application . Their shade range is incomplete. They are mainly used for cottons and sometimes woolens, mostly for printing. These dyes have good light, wash, and dry- cleaning fastness along with having food resistance to perspiration, rubbing, sea water and bleeding. DYES

A mordant is a substance used to set dyes on fabrics by forming a coordination complex with the dye which then attaches to the fabric. STAGES OF DYEING

▪ Stock dyeing at the fiber stage ▪ Top dyeing at the sliver stage ▪ Dope dyeing before a man made fiber is extruded from the spinneret ▪ Yarn dyeing after the fiber has been spun into yarn ▪ Piece dyeing after the yarn has been constructed into fabric ▪ Garment dyeing after the apparel has been constructed METHODS OF DYEING

The process of dyeing can also be classified on the basis of the dyeing methods. The following are the three methods of combining the dye with the textile: • Batch Dyeing : Textile is circulated in a dye-bath • Package Dyeing : Dye-bath is circulated around the textile • Combination Dyeing : Both textile and dye-bath are circulated together. a)Batch dyeing

Batch dyeing is also known as exhaust dyeing. In this process, the textile is circulated through the dye-bath. The process has good flexibility in terms of color selection and low cost. Temperature can be controlled depending on the dye fiber combination. Beck dyeing, jig dyeing and pad dyeing are some examples of this type of dyeing. Winch dyeing

 The winch or beck dyeing machine is oldest form of piece dyeing machine.  It is suitable for practical all types of fabric, especially light weights, which can normally withstand creasing when in rope form as woolen and silk fabric, loosely woven cotton and synthetic fabrics, circular and warp knitted fabrics.  This a dyeing machine for fabrics in rope forms with stationary liquor and moving material. Winch dyeing machine Jigger dyeing

 Jigger dyeing machine is the most commonly used for dyeing all kinds of cotton fabric. There are mainly two types of jigger dyeing machine. One is open jigger dyeing machine and other is closed jigger dyeing machine. This machine consists of V shaped stainless steel vessel. Two rollers are fitted above the vessel called as cloth rollers. These rollers are rotated by power. Out of these two rollers one roller is driven by a motor which is called take up roller and the other roller from which the cloth is delivered is called let off roller. When all the cloth is passed from the let off roller to the take up roller, it is called as one end or one turn. The number of ends or turns depends upon the type of the fabric and also the percentage of the shade. Jigger dyeing machine b) Package dyeing

In Package dyeing, the dye-bath is forced through the textile. Normally, the textile is in yarn stage but the technique is also used for some fiber or fabric dyeing. Examples include beam dyeing, skein dyeing, package dyeing, stock dyeing and top dyeing. Package dyeing machine c)Combination Dyeing

In combination dyeing, both textile and dye-bath are circulated, for example, jet dyeing, paddle machine dyeing. Jet dyeing

 Jet dyeing is a process that can be used for batch dyeing operations such as dyeing, bleaching, washing and rinsing.  In this process, dyeing is accomplished in a closed tubular system, basically composed of an impeller pump and a shallow dye bath.  The fabric to be dyed is loosely collapsed in a form of a rope, and tied into a loop.  The impeller pump supplies a jet of dye solution, propelled by water and/or air, which transport the fabric within the dyeing system ,surrounded by dye liquor , under optimum conditions.  Turbulence created by the jet aids in dye penetration and prevents the fabric from touching the walls of the tube, thus minimizing mechanical impact on the fabric. Jet dyeing Padding machine

Padding mangle offer continuous process of the fabric in concerned liquor , such as pretreatment, dyeing or finishing. Application of dyestuffs is conducted in the pad dyeing machines with single or multiple dipping in solution. During padding, the fabric passes into a solution of chemicals, under a submerged roller and out of the bath. It is then squeezed to remove excess solution . Padding machine PRINTING

Printing is coloring applied to pre-planned areas of a fabric surface. In printing, a pattern to a design is imprinted on the fabric in in one or more colors using dyes or pigments in paste form or by other means. PRINTING

The printing paste is made up of the following ingredients along with the colorant: • Catalysis : Help bond the pigment to the fiber. • Opacifiers : Give different type of luster, such as flossy, matte, and metallic, to the print and produce a pigment with good covering power. • Thickeners : Help produce dark shades. They are added to avoid migration of the paste to surrounding areas. • Thinners : Help to thin down a thick paste when added. PRINTING

• Anti-bleeding agents: Eliminate the halo effect, keeping the print edges sharp and clear. • Softeners : Help maintain a soft hand. • Retarders : Help slow down the drying process when added to the paste. This is helpful in the maintenance of screens. • Dryers : Help speed up the drying process in slow-drying pigments. Classification of printing TYPES OF PRINTS a).Direct Prints In direct prints, color in the form of printing paste is applied directly to the fabric in pattern. This method of manufacturing the direct prints is easy and economical. These are darker color prints on white or light color background. Patterns are sharp at the front side and slightly dull at the back side. Printing methods

Block printing This is a traditional printing method where a block made from wood, rubber, sponge or metal is shaped into a relief pattern (usually using a laser cutter or by hand), then dye is applied to the block and it is hand printed, or stamped, on to fabric. The print can then be repeated several times to achieve a pattern. Block printing Printing method

Screen printing: This method requires a screen, which is a frame with a fine mesh fabric tightly stretched over it. A pattern is either in stencil form or is blocked off on the screen itself, using a screen for each colour to be printed. Dye is pushed through the mesh fabric with a squeegee tool to evenly disperse the dye into the fabric below in the areas that have not been blocked out. Flat-screen printing is done in a similar way but machines operate each stage and often the pattern is applied to the screen digitally. Digital printing is a favored method for small batches of fabric, as screen printing is an expensive process requiring space and specialist equipment. Screen printing Printing method

Engraved Roller Printing Engraved roller printing is an industrial method for large print runs; metal rollers are engraved with a pattern and dye reservoirs apply the color as needed. As in screen printing, a roller is needed for each color; the method is therefore too expensive for short runs of fabric, but it can be very cost-effective for large print runs as hundreds of metres can be printed per minute. Engraved Roller printing Printing method

Stenciling Stencils are made from card. The pattern is cut out and then the dye is sponged or brushed into the cut-out areas. Each stencil can be used several times. Today many stencils are made using computerized cutting machines for more accuracy than hand-cut stencils. Stencil print Printing method

 Digital Printing A design can be made on the computer using computer-aided design (CAD) packages and then either transferred on to paper (sublimation paper), which can be transferred to the fabric with heat, or it can be directly printed on to the fabric using a textile printer and then steam heated to fix the design. In direct printing the fabric may need to be thickened using a special chemical agent, which can be washed out afterwards, to help it feed through the printer. Digital printing Printing method

Rotary screen printing  Rotary screen printing uses seamless cylindrical screens made of metal foil.  The machine uses a rotary screen for each colour. As the fabric is fed under uniform tension into the printer section of the machine, its back is usually coated with an adhesive which causes it to adhere to a conveyor printing blanket.  The fabric passes under the rotating screen through which the printing paste is automatically pumped from pressure tanks.  A squeegee in each rotary screen forces the paste through the screen onto the fabric as it moves along . The fabric then passes to a drying oven. Rotary Screen printing Printing method

 Heat-transfer printing In heat-transfer printing, the pattern is first printed onto a special paper substrate. The paper is then positioned against the fabric and subjected to heat and pressure. The dyes are transferred to the fabric via sublimation. TYPES OF PRINTS

2.Discharge Prints Discharge prints are unique in which the pattern is created by removing color from the selected areas of the fabric and leaving it devoid of any color or introducing another color from where the discharge paste has removed color. This technique is carried out on dark background to attain maximum color effect. TYPES OF PRINTS

3.Resist Prints In Resist prints, color absorption in fabrics is blocked or resisted at the time if yarn or fabric dyeing. There are three different types of resist prints . Types of Resist Prints a)Batik : Batik involves the application of hot wax to resist color application in specified areas. The wax is applied by hand depending on the design and is then left to harden. The fabric is then piece dyed and the hardened wax prevents the penetration of color into the waxed areas. The wax is later removed to get the batik printed fabric. Batik TYPES OF RESIST PRINTS

Tie and Dye: This is also a hand process in which the color penetration is resisted by using tightly tied cotton threads. It is a laborious process producing beautiful result in a number of colors. In tie and dye, the yarn or fabric to be dyed is first tied with thread to resist color penetration in areas as required by the design and then dyed in the first color, which is lightest of all. This process of tying and dyeing continues till the product is colored in its final color. Tie and Dye TYPES OF RESIST PRINTS

Ikat : Ikat is a traditional art of weaving in which the yarn is tied in a pattern specified by the design to resist color from entering in those areas. The yarn is then dyed and the ready yarn is used to weave a fabric in which the design can be formed by only warp dyeing, weft dyeing, or a combination of warp and weft dyeing. These techniques are know as warp ikat, weft ikat and double ikat, respectively. Ikat dyeing Thank you