Dyeing Cotton Knit Goods without Bleaching (Part-2)

Scope of Dyeing Cotton Knit Goods without Bleaching Operation for Energy Saving and Cost Reduction (Part-2)
Md. Palash Hossain
Department of Textile Engineering
Dhaka University of Engineering & Technology (DUET)
Email: palashsakal@yahoo.com


Previous Part


2.2 Methods:
Method followed: Exhaust Method

2.2.1 PROCESSES FOLLOWED IN LABORATORY TRIAL:


A. Pretreatment:

Table 6: Recipe for pretreatment

With Bleaching

Without Bleaching
Name of chemicals
Quantity (g/l)
Name of chemicals
Quantity (g/l)
Wetting agent
1.5
Wetting agent
1.5
Sequestering agent
1.5
Sequestering agent
1.5
Caustic soda                                (NaOH)
5
Caustic  soda                               (NaOH)
5
Hydrogen peroxide(H2O2)
5
-
-
Stabilizer
1.5
-
-
Peroxide killer
0.05
-
-
M:L
1:10
M:L
1:10
Temperature
100oc
Temperature
100oc

Sequence followed in scouring & bleaching:
Figure-1: Scouring and bleaching procedure scheme in IR lab dyeing machine
Sequence followed in scouring without bleaching:
Figure-2: Scouring without bleaching procedure scheme in IR lab dyeing machine
Working procedure:
All the chemicals were taken according to recipe. 10% stock solution of caustic soda was prepared. Then the samples were given in scouring bath. The program was set for 40 min at 1050c. After unloading of the samples normal wash were done for 5 minutes. Then peroxide killer was used in conventional way for removing H2O2 from the fabric at 800c for 15-20 min. After that acid wash was done for the both samples for 10 min. Then hot wash was performed with detergent for 10 min at 800c. Finally cold wash was done.
Figure-3: Infra Red lab dyeing machine
A. Dyeing:
Table 7: Recipe for lab dyeing (0.5% shade)

With peroxide treated fabric

Without peroxide treated fabric
Name of chemicals
Amount(g/l)
Name of chemicals
Amount(g/l)
Leveling agent
1.5
Leveling agent
1.5
Wetting agent
1.5
Wetting agent
1.5
G. Salt
25
G. Salt
25
Soda ash
8
Soda ash
8
Detergent
1
Detergent
1

Working procedure:

Stock solution preparation: During the lab dip, little amount of dyes and other chemicals were required. 1 gm of dye has been taken in 100 ml of warm water and was made as 1% stock solution of dye. Similarly 20% of Na2CO3 (Sodium carbonate) and 20% of Gluber salt solution have been prepared. The formulae below was exercised to get the accurate amount of dyes and chemicals

Sample preparation: The pretreated fabric had been cut and made sample of 5 gm by electronic balance. The sample size was required as rectangular to assess rubbing fastness test. Then all the samples ware soaked in distilled water for few minutes and squeezed well which then got ready for dyeing. 

Dyeing : All the auxiliaries, salt and dyes were placed in dye bath from stock solution and water was taken to maintain 1:10 liquor ratio. Then fabric was added in dye bath at room temperature and run for 5 minute. Temperature was gradually increased (2o/min) up to 60oC. At this temperature the system was run for 15 min and soda dosing was performed for 45 min. After Completing dyeing the dye liquor was drained out. 

After treatment: Normal wash was done. Then hot wash was performed at 80oC with detergent for 10 min. Finally cold wash has been done for 5 min followed by drying at 100oc for 20 min.


Sequence followed in laboratory dyeing:
Figure- 4: Dyeing procedure scheme in IR lab dyeing machine
2.2.2 PROCESS FOLLOWED IN BULK TRIAL:

Specification of used machineries:
  • Machine name-MCS
  • Origin-Italy
  • Machine capacity-1500 kg
  • Maximum capacity for single jersey-1000 kg
  • Maximum Temperature 13000c
  • Maximum water capacity-11200 liter
  • No. of nozzle-06
A. Pretreatment:
Recipe for 1000 kg knitted (S/J) Fabric:
Table 8: Recipe of pretreatment process for bulk production
 
Working procedure:
Conventional
process
Proposed
process
Steps
Tem
Time
Steps
Tem
Time
Fabric loading
20 min
Fabric loading
20 min
Addition(detergent + seq. agent + anti
creasing + stabilizer)
500c
5min
Add (detergent + seq. agent )
500c
3 min
Caustic dosing
500c
5 min
Caustic dosing
500c
5 min
Rising temperature and addition H2O2
700c
10 min
Rising temperature
800c
15 min
Rising temperature
980c
15 min
Run time
30 min
Run time
60 min
Drain out + fill
5 min
Cooling
800c
10 min
Hot wash
800c
10 min
Drain out + fill
5min
Drain out + fill
5 min
Hot wash
800c
10 min
Neutralization
600c
15 min
Drain out + fill
5 min
Enzymes wash
550c
60 min
Peroxide killer
900c
10 min
Drain out + fill
5 min
Drain out + fill
5 min
Washing
10 min
Neutralization
600c
15 min
Drain out + fill
5 min
Enzymes wash
550c
60 min
Drain out + fill
5 min
Washing
10 min
Drain out + fill
5 min
Total
time
255
min
Total
time
188
min
























 
 
A.Dyeing:
Recipe:
Table 9: Recipe for dyeing and after treatment
Conventional process
Proposed process
Name of dyes
& chemicals
Brand name
g/l
Name of dyes
& chemicals
Brand name
g/l
Leveling agent
Dekoven-LVR
1
Leveling agent
Dekoven-LVR
0.5
Anticr . agent
Rucolin-JES
1
Anticr . agent
Rucolin-JES
2
A.acid
Ruco Acid
1
A.acid
Ruco Acid
1
G.salt
30
A.acid
Ruco Acid
0.75
Yellow
Polafix Yellow
3RS
1.0%
Yellow
Polafix Yellow
3RS
1.0%
Red
Polafix Red
3BS
0.3%
Red
Polafix Red
3BS
0.3%
Black
Polafix Black
B
0.7%
Black
Polafix Black
B
0.72%
Soda
12
Soda
12
Soaping  agent
Albatex-AD
0.5
Soaping  agent
Albatex-AD
0.5
Fixing agent
Neofix-R250
0.5
Fixing agent
Neofix-R250
0.5
Softener
Sapamine-CWS
1
Softener
Sapamine-CWS
1

Working procedure:
Sequence followed in dying:

Conventional Process

Proposed process
Steps
Tem
Time (min)
Steps
Tem
Time            (min)
Add leveling
500c

Add leveling
500c

Salt dosing
500c
10
Salt dosing
500c
10
Color dosing
500c
15
Color dosing
500c
15
Run time

10
Run time

10
Soda ash dosing
500c
20
Soda ash dosing
500c
20
Fixation
600c
60

Fixation

600c
60
Drain out + fill

5
Drain out + fill

5
Total time
120 min

Total time
120 min

Sequence followed in after treatment:
Conventional process
Proposed process
Steps
Tem
Time
Steps
Tem
Time
Normal wash
10
Normal wash
10
Drain out +
fill
5
Drain out +
fill
5
Hot
wash(soaping)
800c
10
Hot
wash(soaping)
800c
10
Drain out +
fill
5
Drain out +
fill
5
Normal wash
10
Normal wash
10
Drain out +
fill
5
Drain out +
fill
5
Neutralization
10
Neutralization
10
Drain out +
fill
5
Drain out +
fill
5
Fixing
10
Fixing
10
Drain out +
fill
5
Drain out +
fill
5
Softening
10
Softening
10
Drain out +
fill
5
Drain out +
fill
5
Unload
20
Unload
20
Total time
110
Total time
110

2.2.3 PROCESS FOLLOWED IN TESTING

A. Color fastness to wash
Method followed: ISO 105 C03

B. Color fastness to rubbing /crocking
Method followed: EN ISO 105×12

C. Color fastness to perspiration:
Method followed : ISO105E02 

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