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 Singeing Desizing Scouring Printing Mercerizing Bleaching Dyeing

6. Scouring Printing Mercerizing Bleaching Dyeing Finishing Final inspection Delivery

7. Grey fabric inspection Batching Singeing Mercerizing Scouring Bleaching Printing Dyeing Finishing Final Inspection Delivery

8. Successive stage of Dyeing Electrical double layer Fibre Dye is dispersed in the dye bath Diffusion layer A + - + - + - + - + - + - + - + - + - + - Diffusion layer thickne ss Dye in the diffusion layer Dye molecule Dye in the electrical double layer Dye is absorbed on the fibre surface B Dye is diffused in the fibre Distance of fibre surface from AB Bond formation between dye & fibre

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 substantively of the dyes, and their stability in the dye bath. Lower pH values improve exhaustion; however, leveling proceeds preferably at higher pH values. pH value influences solubility,  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 introduced for color metering of dyes and auxiliaries, and automatic control of the dyeing process. have measurement, been

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 .