Effect of Pretreatment Process on Dyeing of Viscose Fabric with Reactive Dyestuff

Mohammod Habibur Rahman & Ataur Rahman
Department of Textile Engineering
Dhaka University of Engineering & Technology (DUET)
Gazipur-1700, Bangladesh

Objects:

To increase quality of dyed fabric.
Cost minimization
Best process selection
Observation of different pretreatment process
Compare various pretreatment process

Operational activities:

1. Scouring & bleaching:

Different amount of wetting agent use.
Different amount of detergent use.
Different types of detergent use.
Different amount of caustic soda (NaOH) and soda ash (Na₂CO₃) apply.
Different amount of Hydrogen peroxide (H₂O₂) use.
Various liquor ratio use.

Note: When one parameter change then others parameter will remain constant.

2. Dyeing:
Our main object is to observation of different pretreatment process effect for same dyeing recipe. Which process gives us better result.

3. Finishing

Methodology:
The methodology is as follows-

Planning & budgeting

↓

Collection of viscose fabric

↓

Collection of chemicals & dyes

↓

Various pretreatment & dyeing procedure

↓

Observation of results

↓

Compare of results

↓

Select best alternative

Chemicals and Dyes:

1.Wetting agent
Detergent
Sequestering agent
Caustic soda (NaOH)
Soda ash (Na₂CO₃)
Stabilizer
Anti creasing agent
Antifoaming agent
Salt
Hydrogen per oxide (H₂O₂)
Acetic acid
Leveling agent
Softener
Enzyme
Peroxide killer
Lubricant
Dyes
Bicromate or fitcary
Copper sulphate

Modal fabric dyeing (Deep Shade):

Fabric construction: 40/s Modal cotton S/J & 20D Lycra, GSM =150, 3424, SL = 2.9 mm Dia = 75″ (open)

Chemicals/ mlt	Recipe	Process	Dozing /inject	Running & pH
Materials	Batch	Heat setting	190°c to 200°c through stentering
Material	Batch	Loading	Take water before start m/c at 1:10
Detergent (NOPS)	1 g/l	Cold wash	Normal temp.	40˚C – 10´
Stabilizer & sequestering (CONL)	0.5 g/l
Anti creasing (NC)	0.5 g/l
Anti forming	0.5 g / l
Viscose color	3 g/l	Scouring & bleaching	Dozing 40˚C – 7´	70˚C – 60´
BD	Before BD absorbency check
Per oxide killer (Biokil)	0.3 g/l		Inject	40˚C – 10´
Hot	–	Washing	–	80˚C -10´
Acetic acid	0.5 g/l	Neutralization	Inject	50˚C – 10´ for pH = 6.00 ~ 7.00
Wash	–	Neutralization	Inject	50˚C – 10´ for pH = 6.00 ~ 7.00
Leveling ( REB)	1 g/l	Leveling	Temperature Increase at 60˚c	60°C – 10 ´
Sequestering (CONL)	0.5 g/l
Anti creasing ( NC )	0.5 g/l
Salt	80 g/l	Migration	5 % dozing 60˚c – 10´95% doz. 10´	60˚C – 10´ 60˚C – 10´ pH below 7
Salt	80 g/l	Migration	5 % dozing 60˚c – 10´95% doz. 10´	60˚C – 10´ 60˚C – 10´ pH below 7

R/T orange ME – 2RL	3.46%	Color	Dozing 60˚C – 20´	60˚C – 10´
EVR. Red 3BS	2.76 %
Cotton blue	0.0044%
Soda ash	20 g/l	Fixation	1% dozing 60˚C – 20´5% – 20´94% – 20´	60˚C – 10´ 60˚C – 10´ pH 10.5 60˚C – 10´
Soda ash
Soda ash
BD	Before BD sample check (Shade)
Acetic acid	0.5 g/l	Neutralization	Inject	40˚C – 10´
BD	Before BD/rinse sample check (Shade)
RSK	1 g/l	Soaping	Inject	80˚C – 10´
BD	Before BD /rinse sample check (Shade & soft)
Fixer	1 g/l	Fixing	Inject	40˚C -10´
Materials	Unloading

Table: Modal fabric dyeing process with Reactive dye

N.B: Viscose fabric dyeing process is same as to Model fabric dyeing process. Do not use caustic & peroxide, viscose color is a multifunctional chemical which perform scouring & bleaching. Viscose fiber has more absorbency than cotton so liquor ratio uses 1:10. So possibility to uneven dye to prevent it used high liquor ratio & carefully dozing salt and soda.