basics of dyeing
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This document discusses the process of dyeing textiles. It explains that there are three main types of dyeing: fiber, yarn and fabric dyeing. The dyeing process involves successive stages including dispersing dye in a dye bath, diffusion of dye onto and into the fiber substrate, and bonding between dye and fiber molecules. Dyes are also classified by their application method and chemical structure. Proper control of dye bath parameters like liquor ratio, electrolyte concentration, pH and temperature are important to ensure efficient dye absorption and an even color. Modern industrial dyeing is automated but still aims to produce textiles with homogeneous color in an economic manner with good colorfastness.
basics of dyeing
- 1. DYEING
- 2. The application and fixing of a dye to a substrate, normally with the intention of obtaining an even distribution through out the substrate.
- 3. There are three types of dyeing : 1. Fibre dyeing. 2. Yarn dyeing. 3. Fabric dyeing: a) Woven dyeing. b) Knit dyeing.
- 4. Grey Yarn inspection Soft Winding Batching & Loading Scouring Bleaching Dyeing Hydro extraction Drying Hard Winding Delivery Final Inspection
- 5. Grey fabric inspection Stitching Brushing Desizing Scouring Bleaching Printing Mercerizing Singeing Dyeing
- 6. Scouring Mercerizing Bleaching Printing Dyeing Finishing Final inspection Delivery
- 7. Batching Mercerizing Scouring Bleaching Dyeing Printing Grey fabric inspection Singeing Finishing Final Inspection Delivery
- 8. Successive stage of Dyeing Dye is dispersed in the dye bath Dye in the diffusion layer Dye in the electrical double layer Dye is absorbed on the fibre surface Dye is diffused in the fibre Bond formation between dye & fibre + - + - + - + - + - + - + - + - + - + - A B Diffusion layer Electrical double layer Diffusion layer thickne ss Distance of fibre surface from AB Fibre Dye molecule
- 9. According to method of application: Direct dye Reactive dye Vat dye Azoic dye Sulphur dye Basic dye Acid dye Disperse dye
- 10. According to the chemical structure: Azo dye Indigoid dye Anthraquinone dye Polymethine dye Styryl dye Nitro & nitroso dye Phthalo cyanine dye Aryl carbonium dye
- 11. Wetting agent Detergent Sequestering agent Leveling agent Anti foaming agent Dispersing agent Anti creasing agent carrier
- 12. Two types of dye application techniques exist: 1) Direct application of dye liquor by spraying, foam application, or printing. 2) Continuous immersion of the fabric in a dye bath and removal of the excess of liquor by squeezing or suction (padding).
- 13. 1.Continuous dyeing processes Pad dry process Pad steam process 2.Semi continuous processes Pad-batch process Pad jig process 3.Discontinous process: Winch Jet Jigger 4.Pad Dyeing Processes: Pad roll process
- 14. The goal of every dyeing is a colored textile in the desired shade, homogeneous in hue and depth of shade, produced by an economic process and which exhibits satisfactory fastness properties in the finished state.
- 15. Basically there are three methods of dyeing textiles: 1) Mass dyeing: dyeing of a synthetic polymer before fiber formation. 2) Pigment dyeing: affixing an insoluble colorant on the fiber surface with a binder. 3) Exhaustion dyeing from an aqueous bath with dyes that have an affinity for the fiber.
- 16. The liquor ratio influences the dye solubility and the strength of the electrolyte effect. Lower liquor ratios are employed whenever possible, for ecological, economic, and technical reasons. The electrolyte (i.e., sodium chloride or sodium sulfate), its concentration, and the speed of addition control the adsorptive behavior of the dyes and the degree of exhaustion. A high electrolyte content of the dye bath shifts the dyeing equilibrium toward the fiber.
- 17. The pH value influences solubility, substantively of the dyes, and their stability in the dye bath. Lower pH values improve exhaustion; however, leveling proceeds preferably at higher pH values. Temperature generally determines the position of the dyeing equilibrium, which at room temperature is shifted strongly toward adsorption on the fiber.
- 18. Colored textiles are produced today on a large industrial scale. Although modern automation techniques have been introduced for color measurement, metering of dyes and auxiliaries, and automatic control of the dyeing process.
- 19. We would like to express many thanks to our honorable teacher Prof. Dr. Zulhash Uddin giving us a very good opportunity for presenting ourselves. We also thanks our parents who encouraged us every step of our life. Lastly thanks all of you who are give kind attention for this presentation ceremony .