Textile: Sodium Hydroxide and 2. 3. 4. 5. 6. 7. 8

Topics: Sodium hydroxide, Water, Bleach Pages: 6 (1384 words) Published: May 19, 2013
Module Title: Textile Dyeing, Printing & Finishing. Module Code: TEX-203 Teacher Name: Md. Sadiqur Rahman Reference Book:  Dyeing and Chemical Technology of Textile Fiber. By – E.R. Trotman  Dyeing and Chemical Technology. By- V.A. Shenai Lecture: 02 Wet Processing: Wet processing is a technology which convents in grey fabric into finished fabric by the application of dye, water and auxiliaries. Wet processing is the combination of dyeing, printing and finishing. Sequence/Flow chart of wet processing:

Inspection of grey fabric Brushing Stitching Shearing and cropping Singeing Desizing Scouring Souring Bleaching (Optional) Mercerizing Dyeing Printing Washing Drying Finishing (Cotton/Flax) (Alkali) (Acid)

General theory of dyeing Dyeing is the process of coloring textile material by immersing them in on aqueous solution of dye which is called dye liquor to improve the off effectiveness of dyeing heat is applied in to the dye liquor the generally theory of dyeing explain the interaction among dye fabric and water. It explains: 1. Force of repulsion 2. Force attraction Force of repulsion Which are developed between dye molecules and water molecules?

Force of Attraction: Which are developed between dye molecules and fabric?

Basic dyeing curve:

Y Temperature (c`) 100 Soda 80 (X-30 = Y80) 60 Salt 40 (X-90 = Y-80)


(X-20 = Y-20)

(X-100 = Y-20)

Drop Liquor

Fabric (Day+Water+ auxiliaries) 10 20 30 40 50 60 70 80 90 100 X

Time (Min)

Lecture: 03 Singeing: Singeing is the pre-treatment of wet processing to remove all the projecting, loose and hairy fibers by the application of heat. Objectives: 1. To remove all the projective, loose and hairy fibers. 2. To improve the lecture of dyeing. 3. For even dyeing and printing. Singeing Machine:

1. Plate singeing machine.  CU Plate  Thickness 1-4”  150-250 yards /min fabric speed.  Guide roller, 1 pair of drawing roller. Dyeing Roller Draw Roller Left to right fabric move

2. Rotary cylinder singeing machine.  Cylinder  80-150 yards / min  Guide roller

3. Gas singeing machine  Gas Burner  250-400 yards / min fabric speed.  Brushing system  Washing tank  Guide roller, drawing roller, squeezing roller.

Copper Plate

Desizing: Desizing is the pre-treatment of wet processing to remove the size materials from the warp yarn is called Desizing. Objectives: 1. To remove the size materials. 2. To increase the absorbency of water and chemical. 3. To convert hydrophobic nature into hydrophilic nature.

Types of Desizing: Desizing



Rot Steeping 24 hours 40`C

Acid Alkali Steeping Steeping 8-12 hours 8-12 hours 0.25% - 30`c 0.25%

Enzyme Steeping 3-4 hours 50`c-60`c

Chlorine 30-45min


Chlorite 30-45min



Molt Name of Enzyme: 1. 2. 3. 4. 5. Scouring: Parcretic Biolase Diastase Diastafore Degomma


Scouring is the pre-treatment of wet processing to remove all impurities such as oil ,fat, wax & dust found in the textile material by using Alkali such as Na2Co3 etc. is called Scouring. Objectives: 1. To remove impurities such as oil, wax, fat etc. 2. To convert hydrophobic nature into hydrophilic nature. 3. Increase the absorbency of water and chemical.

Name scouring machine: 1. 2. 3. 4. 5. 6. 7. 8. High / Low pressure kier boiler (cotton, woven) Ge baur’s kier (cotton, woven) Harrow rack machine (wool) Zet scouring machine (wool) Levien scouring machine (wool) Rotary dolly scouring machine (knit) J-Box scouring machine (cotton) Vapour loc scouring machine (any type fabric maximum 2.5 min )

Lecture: 04

Scouring Mechanism: 1. Saponification: Saponification is the process of removing animal fat or oil from the fabric wing NaOH (sodium hydroxide) 2. Emulsification: Emulsification is the process of removing mineral oil from the fabric using soup solution or NaOH. Detergency: Detergency is the process of removing solid particles such as dirt, dust and...
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