what we have got from experimentation so that we expect from the test result of the lab.

1. Indian Institute of Technology-Delhi
Department of Textile Technology
PRESENTED TO:
PROF. SAMRAT MUKHOPADHYAY
PRESENTED BY:
ABEBE TEKA(2015TTF2839)
MULUNEH CHALIE(2015TTF2837)
RAPID AND CONVENTIONAL DYEING OF PET FABRIC
1

2. Objective
2
To assess the effect of Rapid and Conventional Dyeing
methods on colour strength of Polyester Fabric using
disperse dye.

3. Theoretical Basis of Rapid dyeing Methods
3
 The dyeing cycle in a conventional exhaust procedure occur
simultaneously, but for a theoretical discussion of the dyeing
cycle they can be considered separately.
fig 1: phase of an exhaust dyeing process

4. Theoretical Basis of Rapid dyeing Methods
4
Exhaust phase
 depends firstly on the rate of heating, but also on the
replacement speed of the liquor at the fibre surface.
→ In circulating-liquor machines with stationary goods the
critical factor is the speed of liquor circulation.
→ In both liquor and goods are in motion - the frequency of
contact per unit time between goods and fresh liquor
Diffusion phase
 dependent on both time and temperature, but is not
affected by the speed of either goods or liquor
Migration phase
 compensate for local concentration differences until finally
an even distribution is achieved.
 greatly affected by type of dye and temperature.

5. Theoretical Basis of Rapid dyeing Methods
5
Level dyeing's can be obtained in two different ways
1. Controlled adsorption
 levelling happens during the exhaust phase by suitably
controlling the rate of exhaustion as a function of
temperature and rate of liquor circulation.
2. Controlled migration
 degree of un levelness during the exhaust phase is
deliberately accepted and a sufficiently long migration phase
is allowed for subsequent equalization of the concentration
differences.

6. Theoretical Basis of Rapid dyeing Methods
6
Aim of Rapid dyeing
The aim is not just to save as much time as possible, but also to
ensure dependability of results, i.e. levelness and good
reproducibility
principle of rapid dyeing of polyester
The first proposal by Carbonell and Lerch
“during the heating phase only a given, constant amount of each
dye can exhaust in each temperature range, irrespective of the
original total amount of dye present in the bath”.
 According to Carbonell’s theory, the final 80% of the dye in
the bath should exhaust at a rate not faster than 1% per bath
cycle, whereas the first 20% does not determine the levelness
 and the temp. at which this phenomena occurs is the critical
temp. range

7. Theoretical Basis of Rapid dyeing
Methods
7
 Standard temperature exhaust at a rate of 1% of the
initial amount per minute onto a standard polyester
material.
 This temperature is the starting point of the critical
temperature range in which the dyebath has to be heated
at a controlled rate of 0.5-3°C per minute.
 This critical range spans a temperature interval of 20-
25°C.
 Above and below it the bath can be heated rapidly.

8. Material and methodology
8
Dyeing
Chemical Unit Rapid Conventional
Disperse Dye shade 3% 3%
Dispersing Agent g/l 1 1
PH 4.5-5.5 4.5-5.5
MLR 1:40 1:40
Chemical Unit Rapid Conventional
Hydros g/l 2 2
Caustic Soda g/l 2 2
Temp 80 80
Time 30 30
MLR 1:40 1:40
Reduction cleaning

9. Material and methodology
9
Procedure
Prepare the fabric and weigh
Prepare the solution as per the recipe
Dye using laboratory HTHP machine according to the
dyeing cycle
 Wash and Drying at 110oc
Performing Reduction clearing as per the recipe
Wash and dry at 110oc
Assess the KS value and E with spectrophotometer

10. Results and Discussion
 DYEING CYCLE
 Conventional Dyeing cycle
10
Temperature
C
Time(min
)
Heating Rate(C/min)
60-130 35 2
130 60 0
130-60 25 -2.8
150
120
Temp(°)Temp(°)
90
60
25 50 75 100 125
Time (min)
Temp(°)
130°C 130°C
95 C
60°C

11. Results and Discussion
■ Rapid dyeing Cycle
11
Temperature
C
Time(min
)
Heating Rate(C/min)
60-95 17.5 2
95-115 20 1
115-130 7.5 2
130 15 0
130-60 25 -2.8
150
120
Temp(°)Temp(°)
90
60
25 50 75 100
Time (min)
Temp(°)
115°C
130°C
95 C
60°C

12. Results and Discussion
12
Type of
Dyeing
L* a* b* C* h* CB-
SWL
De*
Convention
al
48.33 13.87 37.22 39.72 69.55 12.423
Rapid 61.1 19.34 56.95 60.14 71.24 15.626 24.13
Results of the ks value and colour differences for the two cycle
0
10
20
30
40
50
60
70
80
L* a* b* C* h* CB-SWL
Conventional
Rapid

13. Conclusion
 In this experiment 35 min is saved 30% of time saving
 Thus this can automatically improve the productivity
 the colour strength is 15.626 and 12.423 for rapid and
conventional dyeing respectively.
 The color strength shows an improvement of 26% in
rapid.
 E* value also shows higher differences between the two
samples
 Therefore, Rapid dyeing method of polyester with
disperse dye gives not only save time but also improves
the color strength and yield under the recipe specified.
13

14. References
 G.Siegrist, Developments in Rapid Dyeing Methods and
Machinery, Rev. Prog. Coloration. Vol.8 1977
14

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