1. GREEN UNIVERSITY OF BANGLADESH
Department Of Textile
Lab Report
Course Code : TE 413D
Course Title : Apparel Manufacturing III Lab
No Of Experiment : 06
Name Of Experiment : Study on acid washing process of garments.
Remarks:
Submitted By:
Name : Md Rakibul Hassan
ID : 183014057
Section : E2
Department : Textile
Submitted to:
Name : Jannat Jahan Joya
Designation : Lecturer
Department : Textile

2. Experiment No: 06
Experiment Name: Study on acid washing process of garments.
Introduction:
Acid wash is a process in which a denim garment is treated with a bleach solution containing chlorine-
soaked stones so that the color becomes faded and the material is softer. In case of acid wash, pumic
stones are used. By the action of pumic stones, an irregular fading effect is developed on heavy
garments like denim, thick canvas/twill, and sweaters. The pumic stones act a brushing action on the
garment fabric surface. A fading effect may be developed on the garment by acid wash technique.
The acid washing process was created in Italy and patented in 1986. Garments made from heavy jeans
and denim fabrics, course canvas, sweaters, and thick twill, etc. are washed by applying the acid wash
technique. By applying the acid wash technique, an irregular pattern fading effect is produced in the
garments, where the effects are more pronounced than stone wash. Acid wash is a very dirty process
due to the widespread use of pumice stone.
Acid Washed Shirt Acid Washed Jeans
Objectives:
1. To Learn about acid wash
2. To learn about acid washing process of garments
3. To create irregular fading effects on the garments surface
4. To get vintage look
5. To fulfill the buyer washing standard
6. To increase rubbing fastness
7. To improve softness
Process Flow Chart Of Acid Wash:
Garments loading in machine
↓
De-size
↓
Extracting the garments
↓
Drying
↓
Soaking of pumice stone
↓
Damp pumice stone

3. ↓
Neutralization the garments
↓
Softening
↓
Extracting the garments
↓
Drying
Description:
Working procedure of acid washing:
1. Garments loading in the machine:
It is the first process of the acid wash. The required amount of clothing is loaded in the machine here
for de-sizing the garments.
2. De-size:
The garments are de-sized here by using detergent and de-sizing agent. The required amount of de-
sizing agent should be applied here by following M: L ratio. Here, sometimes needed 50-60° C
temperature depends on the shade. De-size should be done at least 15-20minutes.
3. Extracting the garments:
After completing the desizing process, the garments are squeezed here by using the hydro-extractor
machine and send to the drying section.
4. Drying:
Here the extracted garments are dried by using a gas dryer or steam dryer depending on the shade. It
should be noted here that, the gas dryer is used for reddish shade and the steam dryer is used for bluish
shade.
5. Soaking of pumice stone:
The fresh pumice stones are soaked here at room temperature for 10minutes by shuffling using
Potassium permanganate (KMnO4) and Phosphoric acid (H3PO4) containing the liquor ratio 1:2.
Pumice stones are naturally perforated and should pick up the solution very quickly.
6. Damp pumice stone:
After the required soaking of pumice stone, the completely dried de-sized garments are treated in the
machine with damp pumice stones at room temperature for 15 minutes (depending on the shade).
After completing this process, garments are unloaded from the machine and loaded in another
washing machine for neutralized the garments.
7. Neutralization of the garments:
After completing the damp pumice stone process, the garments must be neutralized here by using
Sodium meta-bisulfite (Na2S2O3) containing the liquor ratio (M: L) for 5minutes (depending on the
shade).
8. Softening:
Here the garments are producing the too soft effect by using softening chemical containing liquor
ratio (M: L). After completing this process, garments are unloaded from the machine.
9. Extracting the garments:
Here the acid-washed garments are extracted and send to the drying section.

4. 10. Drying:
Finally, the garments are drying here by using a gas dryer or steam dryer depending on the shade.
Limitation of acid washing:
Due to high abrasion between fabric and stones, heavy fabric is required to create random effect.
The major cause is residual manganese due to incomplete neutralization, washing or rinsing.
Indigo dyed denim has a tendency to yellow after random washing.
Conclusion:
After doing this experiment we have learnt about acid wash and the process of acid washing of
garments. This will be helpful to all textile engineers. Lots of thanks to our honourable teacher.