Scouring process,overview of textils scouring

                 Scouring is a process by which all natural & additive impurities such as oil, wax, fat, hand dust, etc. are removed to produce a hydrophilic & clean textile material. It is one of the vital processes of wet processing. On cotton fibers, this treatment removes fatty and pectic substances, softening motes and

preparing the material to absorb the subsequent treatment agents.

Objects:

1.    To make the fabric highly hydrophilic.

2.    To remove impurities such as oils, waxes, gum, husks as nearly as possible.

3.    To increase absorbency of fabric or textile materials without physical & chemical damage.

4.    To produce a clean material by adding alkali.

5.    To make the fabric ready for the next process.

6.    To remove non-cellulosic substance in case of cotton.                                                                                                                                                                                                                      

Scouring process depends on:

1.    The type of cotton.

2.    The color of cotton.

3.    The cleanliness of cotton.

4.    The twist & count of yarn.

5.    The construction of the fabric.

6.    The shade% & type of shade of finished product.

                                                                                                                Chemicals used in Scouring process:

Main Chemicals	Use
Caustic soda	Neutralize acidic materials, saponify glycerides, solubilise silicates.
Surfactants	Reduce surface tension & minimize interfacial tension.
Detergents	Emulsify oil, fats, waxes, & remove oil-borne stains.
Chelating agents	Deactivate metal ions.
Sodium silicate	Penetrate & break down lignins.
Soda ash	Maintain pH.
Solvent	Assist emulsification by dissolving oily materials,

Scouring process:

1.    Batch process.

2.    Semi-continuous process.

3.    Discontinuous process.

4.    Modern process.

 

kier boiler

Scouring process of cotton:

Generally, there are two principle of cotton scouring.

1.    Discontinuous (kier boiling process or winch dyeing machine )

2.    Continuous (scouring in ‘J’ or ‘L’ box) 

                                       J box Process

Scouring process of silk:

ʘ Impurities present in silk.

ʘ Sericin up to 30% (main impurities)

Mineral matter, coloring matter, traces of waxes & fats =1-1.5%

ʘ the removing of these impurities in silk are called degumming.

Scouring of jute :(Bast fiber)

ʘ Bast fiber, jute, linen etc. multicellular fiber, having polygonal shape. The cells are cemented with each other by lignin which is non-cellulosic unit & is about 11-14%.

ʘ If strong alkali is used for jute scouring, its strength is reduced as lignin is removed & cells are separated. So mild alkali is used in jute scouring at low temperature.

Assessment of Scouring:

1. Drop test:

ʘ In a pipette, a solution of 0.1% direct red or congo red is taken & droplet of solution put on the different places of the fabric. Then the absorption time of the fabric is observed.

ʘ The standard time of absorption of one drop of solution is 0.5-0.8 sec.

                              

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Writer and editor SABBIR

I am Nur Mohammed From comilla,Bangladesh.I studied in Textile Engineering and very much fond of blogging; so try to write about Textile