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 .