Dyeing Techniques for textiles and etc.ppt
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Stock dyeing and top dyeing refer to dyeing fibers before spinning into yarn to produce soft, heathered colors. Yarn dyeing dyes yarn to create patterns like stripes and checks. Common yarn dyeing methods are stock, package, and skein dyeing. Piece dyeing dyes constructed fabrics in batches for flexibility. Beck and jig dyeing are continuous piece dyeing processes. Garment dyeing dyes finished apparel products to meet fashion demands quickly.
Dyeing Techniques for textiles and etc.ppt
- 2. STOCK/TOP Dyeing • Stock dyeing refers to the dyeing of fibers, or stock, before it is spun into yarn. It is done by putting loose, un-spun fibers into large vats containing the dye bath, which is less than heated to proper temperature. From 500 to 3000 pounds (227 to 1364 kgs.) of fiber are dyed at one time, and the average is about 1000 pounds (454 kgs.) • • Top dyeing is also the dyeing of fiber before it is spun into yarn and serves the same purpose as stock dyeing that is to produce soft, heather like color effects. The term top refers to fibers of wool from which shorter fibers have been removed. Top is thus the select long fibers that are used to spin worsted yarn. The top in the form of silver is dyed and then blended with other color of dyed top to produce desired blended heather shades.
- 4. Yarn Dyeing • Yarn dyeing is used to create interesting checks, stripes, and plaids with different-colored yarns in the weaving process. In yarn dyeing, dyestuff penetrates the fibers in the core of the yarn. • Some methods of yarn dyeing are stock, package, and skein dyeing. Stock dyeing dyes fiber using perforated tubes. In package dyeing, spools of yarn are stacked on perforated rods in a rack and immersed in a tank where dye is then forced outward from the rods under pressure. • The dye is then pressured back through the packages toward the center to fully penetrate the entire yarn. Most carded and combed cotton used for knitted outerwear is package-dyed. In skein dyeing, the yarn is loosely coiled on a reel and then dyed. • The coils, or skeins, are hung over a rung and immersed in a dyebath (Corbman, 1975). The skein-dyed yarn is used for bulky acrylic and wool yarns. Typical capacity for package dyeing equipment is 1,210 pounds (550 kg) and for the skein, dyeing equipment is 220 pounds (100 kg).
- 5. Skein Dyeing • Skein dying is a way of dyeing yarn through dipping skeins or loosely wound hands of yarns into dye vats. Yarns used for knitting are typically processed this way. • Skein dyeing is one of the oldest and expensive methods of coloring yarn, but it remains significant for it can color small portions of yarn.
- 6. Package Dyeing • Package dyeing is another way to dye yarn. It takes place while a yarn is wound on a small spool or tube, which is referred to as the package. Several packages of yarn can fit into a dyeing machine at once, which makes the process less expensive. However, package dyeing may result to less soft yarns.
- 8. Piece Dyeing • The most dyed fabric is piece-dyed since this method gives the manufacturer maximum inventory flexibility to meet color demands as fashion changes. In terms of overall volume, the largest amount of dyeing is performed using beck and jig equipment (Figure 11). Beck dyeing is a versatile, continuous process used to dye long yards of fabric. About 1,980 pounds (900 kg) of fabric can be dyed on beck equipment at a time. • The fabric is passed in rope form through the dyebath. The rope moves over a rail onto a reel which immerses it into the dye and then draws the fabric up and forwards to the front of the machine. This process is repeated as long as necessary to dye the material uniformly to the desired color intensity. • Jig dyeing uses the same procedure as beck dyeing, however, the fabric is held on rollers at full width rather than in rope form as it is passed through the dyebath (Corbman, 1975). This reduces fabric tendency to crack or crease. Jig dyeing equipment can handle 550 pounds (250 kg) of fabric.
- 9. Piece Dyeing • Dyeing constructed fabrics is called piece dyeing. The textile manufacturer can dye the whole fabric in batches according to the fashion demands of the time thus avoiding wastage and loss. The great bulk of dyed fabric on the market is dyed in the piece. There are several common methods of piece dyeing. Specific names such as union, cross, tone-on-tone, and reserve dyeing are given to piece dyeing of fabrics containing fibers that exhibit different dyeing characteristics.
- 10. Union Dyeing • A fabric containing fibers that accept dyes from different classes are dyed by this method, with a result that the fabric is dyed in a solid colour. The fabrics can be either blends of two fibers, such as cotton and polyester – or mixtures in which the warp yarns are made of one type and filling of another. The dyeing process includes one bath or two bath methods. By using the blend in various ratios or by randomly using different yarns in weaving sequence good designs can be obtained.
- 11. Cross Dyeing • In cross dyeing, a multicolored fabric is obtained. Fabric containing two or more fibers types is purposely dyed so that each fiber type or variant accepts a different type of dye and becomes a different colour. Fabrics may be composed of – Fibers from different generic group, – Natural and manufactured fibers, or – Manufactured fibers from the same generic group when one fiber has been modified to accept dyes from a different dye class. The end product depends on the fiber arrangement in the fabric.
- 12. Garment dyeing Dye when applied to finished products such as apparels and garments, it is called garment dyeing. This helps the dyer to meet the demands of fashion colours on time and does not require to stock huge amounts of dyed fabrics.
- 13. Piece Dyed vs Yarn Dyed fabric? Fabrics those have stripes and checks patterns are normally weaved using dyed yarns i.e. yarn dyed fabric. (Though check and stripe patterns can be made by printing). Secondly, a multi color woven designs in fabric mostly yarn dyed. Fabrics with solid or single color are mostly piece dyed. Color fastness of piece dyed fabric is less than yarn dyed fabrics. Color fastness is good in yarn dyed fabrics. This means that color of the fabric does not fade away easily. You would not get color bleeding in yarn dyed fabrics. In price point, normally yarn dyed fabric are costlier than a piece dyed fabric
- 15. Garment Dyeing • The process of dyeing fully made apparel product like t-shirts , pants , trousers , shirts , jackets, tops, pullovers , dresses and bottoms is called garments dyeing. In Conventional method , Garments are made with pre-dyed fabrics and then cutting and sewing. But now grey fabrics are dyed in required color after manufacturing. It has become popular in recent days due to cost saving and fashion trends. Also it is capable to react much closer to actual market demand if the apparel is post dyed which reduces lead time and increases forecasting accuracy.
- 16. Advantages of garments dyeing • Lower cost needed • Less time needed • Less shade variations occurs • Flexible lot size • Old garments can be redyed • Lower initial investment • Lower liquor ratio • Desizing , Scouring , Bleaching can be done in same machine • Capable to react with fast changing market trends • Fancy effects can be obtained • Lower inventory • Comparatively lower rejection rate
- 17. Disadvantages of garments dyeing • High cost of processing • More material handling • Special care for selection of interlining • Higher seconds rate in production • Labor intensive process • Requries full checking of all pieces