Port City International University
Department Textile Engineering
Program B.Sc. in Textile Engineering
Course Title Wet Process Engineering-IV
Course Code TEX-485
Engr. Iusuf Khan
Senior Lecturer
Course Teacher Department of Textile Engineering
Port City International University
Course Status Core
Study on Estimation of Scouring Effect
Assignment Name
Mohammad Tayub (ID-BTE01606091)
Submitted By Antu Mallick (ID-BTE 01606105)
Date of Submission 24/11/2021
Study on Estimation of Scouring Effect
Introduction: Textile wet processing is one of the major streams in textile engineering refers to
textile chemical processing and applied science. It is usually done on the manufactured assembly
of interlacing fibers, filaments, or yarns having a substantial surface area in relation to their
thickness, and adequate mechanical strength to give it a cohesive structure. An alternative way to
say, the wet process is done on manufactured fabric. The processes of this stream are carried out
in an aqueous stage and thus it is called a wet process which usually covers pretreatment, dyeing,
printing, and finishing. All of these stages are required an aqueous medium that is created by water.
These processes require plenty of water every day. It is estimated that, on average, almost 100-110
liter of water is used to process only 1 kg of textile goods. Water can be of various qualities and
attributes. Not all kinds of water can be used in the textile process, it must have certain
characteristics, quality, color, and properties to be used in the textile process. That is why wet
processing is concerned with water. At this time, we discuss about a scouring & its estimation.
Scouring is the pretreatment process by which oil, wax, fat is removed from fabric. So that fabric
weight will be reduced slightly (in case of good souring 4%-8%) and absorbency of fabric will be
higher for removing of oil, wax, fat etc. Absorbency test are determined by Drop test, Spot test,
Immersion test and column test.
[C01, C03]
Objectives of scouring:
In order to make the material extremely hydrophilic.
To considerably absorb textile products without suffering chemical or physical harm.
A neat material is generated by adding alkaline.
For cotton removal of non-cellulosic material.
In order to make the textile material prepared for subsequent bleaching.
[C01]
Changes occurred during scouring:
1. Free fatty acids are converted into soap.
2. Proteins are hydrolyzed into soluble products.
3. Pectize and pectin are changed into soluble salts of Pactic acid.
4. Mineral matter is dissolved.
5. Dust particles are removed.
6. Residual sizing materials are broken down into soluble products.
[C02]
Scouring process depends on:
1. Types of fabric.
2. Color of fabric.
3. Cleanliness of fabric.
4. Twist of the fabric.
5. Count of the fabric.
6. Construction of the fabric.
[C03]
Flow chart of cotton scouring:
Cotton fabric/fiber
Inspection
Wetted by NaOH solution
Emulsification
Detergency
Washing
Scoured fabric
[C03]
Method of scouring: Scouring may be done separately or in conjunction with other treatments
(usually bleaching or de-sizing) in all types of substrates;
1. Woven fabric (sized or de-sized).
2. Knitted fabric.
3. Yarn.
For yarn and knitted textiles, scouring is typically a batch process carried out on the same material
that is later used for dyeing. Woven fabric is continuously scoured using the pad-steam method.
[C03]
Method is using for scouring;
1. Batch process/Discontinuous process. (By Kier Boiling/Jigger/Winch dyeing
machine)
2. Continuous process. (By J-Box machine)
1. Batch process/Discontinuous process: In the batch or discontinuous process, Kier Boiling
machine is mostly used. There also we used Jigger and Winch dyeing machine.
2. Continuous scouring process: In the Continuous process, J-Box machine is used. It is called J-
Box machine because the scouring vessel looks like the English letter ‘J’. The J-box is mainly a
steel chute with big capacity fabrics. In comparison to a kier where it is first in the last out, the
fabric is supplied from one end and pulled from the other (first out). The internal side of the J-
box is polished and is insulated to minimize thermal losses. De-sizing, scoring, and bleaching can
be performed at once in this system.
[C02]
SL.
Discontinuous Process Continuous Process
No.
In this process fabric is scoured in rope In this process fabric is scoured in open width
1
from. form.
2 This process is suitable for small order. This process is not suitable for small order.
3 Uneconomical process for large order. Economical process for large order
More time required then continuous
4 Less time consumption process
process
[C03]
Estimation of scouring effect:
Measurement of Weight Loss:
5gm of dried sample is treated with 200ml of 1% NaOH for 1hrs at 80deg cel, after which the
sample is well rinsed and rent out in not water. It is then treated in 200ml 0.5% HCL at 80deg cel
for 1hrs, after which the sample is once again rinsed, boiled for 30min. In distilled water dried and
weight. The wt. loss is measured in%.
The measurement of weight loss which are given below-
Wt. loss= (Weight before scouring-Weight after scouring)/Before Scouring ×100%
Wt. loss on scouring is 4 to 6%, the wt. loss will be 9%. It is not required to well scoured the fabric.
Above than 8% or 9% fiber damage occur... i.e., oxy cellulose formation.
Result: Standard weight loss=4.6%
[C03, C04]
Immersion Test:
After scouring absorbency of fabric is increased significantly a scoured sample will take less time
to be immersed into water than an unscoured sample. A predetermined sample (1cm×1cm) sized
is put gently on the surface of fresh water. Then the time in second is recorded by a stop watch for
submerge the sample into water.
Result: The standard time for immersion is 5sec and up to 10sec is acceptable.
[C03, C04]
Drop test or Quick test:
Execute within a short time. In this method, a 0.1% direct (Congo-red) solution is used. A drop of
the solution is taken by a pipette or glass rod and put softly on to the sample surface. The nature
of the absorption is observed carefully.
Two thinks should be considered:
1. The time for absorption the drop.
2.The shape of the absorbed area on the sample surface.
Result: A standard scoured sample will take 0.5-1sec for absorption of the drop.
[C03, C04]
Spot test:
Drop test and Spot test on the fabric visually.
1. Spread over more area - More scouring effect
2. spread over less area - Less scouring effect
3. Spread Irregularly- Uneven Scouring
[C03, C04]
Column test: Scouring is the pretreatment process of wet processing technology. Scouring is
the first Stage of pretreatment. Before dyeing or printing of textile materials must pass scouring
process. Scouring is the process by which natural (oil, wax, gum, fat etc.) as well as added (during
fabrication process) impurities are removed completely as possible. Especially Hydrophobic
character which is present in the fiber of fabric is removed completely as possible. There are
several methods to test optimum scouring effect on treated fabric. Column test is one of that, in
this test method observer the absorbing ability of the material for certain time. The standard range
of absorption is about 30-50mm.
It’s a very reliable test for measuring the scouring effect. A predetermined sample (18cm×5cm)
sized and standard dye solution (0.1% direct dye) is taken to perform the test. A mark is drawn at
1cm above from the sample bottom.
Result: 1. Acceptable absorbing length is 30-50mm.
2. 30mm absorbing length means the acceptable lower limit of scouring.
3. 40-45mm absorbing length means good/very good scouring.
4. 50mm absorbing length means excellent scouring.
[C03, C04]
Conclusion: In conclusion, we can conclude that the process of removing these impurities is
called Scouring. Even though these impurities are not soluble in water but they can be removed by
dissolving in organic solvents, emulsification, forming stable suspensions of the impurities in
water and converting the contaminates into water soluble components.
Before dyeing or printing of textile materials natural fibers must pass scouring process. Scouring
process bears an impotency in wet processing.
[C01]
