Question

What is Scouring ?

Hint:

It is a cleaning step with hot alkali and detergent that removes wax, fats and dirt from grey fabric.

Answer 1

Step 1: Define scouring:
Scouring is a wet cleaning process in which natural and added impurities are removed from the fabric.
It is done after singeing and de-sizing.

Step 2: List the impurities:
Cotton carries natural wax, fats, pectin, proteins and mineral matter.
It may also have dirt and oil picked up in spinning and weaving.
These make the cloth water repellent and yellowish.

Step 3: Explain how it is done:
The fabric is boiled or steamed with an alkaline liquor, usually caustic soda, with soda ash and a detergent or wetting agent.
The alkali turns fats into soap-like substances and loosens the wax and pectin. The detergent carries them away in the wash water.

Step 4: State the benefit:
After scouring the cloth becomes clean and absorbent.
It takes up bleach, dye and finishing chemicals evenly.

Final Answer:
Scouring is the process of removing natural impurities like wax, fats, pectin and dirt from fabric by treating it with alkali and detergent, to make it clean and absorbent.