1. PRE-TREATMENT
IN THE DYEING AND FINISHING PROCESS
Responsible Sourcing Initiative
Natural Resources Defense Council

2. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
First, we will go through: Woven Fabric
Fiber Yarn
Knitted Fabric
Pre-treatment
Dyeing Bleaching Printing
Finishing

3. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
WHAT IS PRE-TREATMENT?
• by damaging the fabric as little as possible, remove
all the impurities from the fabric
• make a semi-finished product that is clean, smooth,
soft, and water absorbent (hydrophilic)
• the preparation work in a dyeing and finishing
factory work, it can also be known as bleaching and
scouring

4. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
THE BASIC COMPONENTS OF PRE-TREATMENT:
SINGEING DE-SIZING SCOURING BLEACHING MERCERIZING
PRE-TREATMENT
NOTE: THIS IS JUST AN EXAMPLE OF THE PRE-
TREATMENT PROCESS FOR COTTON. PRE-TREATMENT
PROCESSES CAN VARY FOR EACH TYPE OF
SUBSTRATE.

5. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
Let’s talk about singeing…
SINGEING DE-SIZING SCOURING BLEACHING MERCERIZING
PRE-TREATMENT

6. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
SINGEING REFERS TO THE BURNING
OFF OF:
- LOOSE FIBERS NOT FIRMLY BOUND
INTO THE YARN OR FABRIC
- LOOSE YARNS NOT BOUND INTO
FABRIC
- PROTRUDING FIBER ENDS STICKING
OUT OF THE YARN OR FABRIC
Information: http://ara-texworld.com

7. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
BEFORE AFTER
SINGEING SINGEING
Photo: Osthoff Senge from http://ara-texworld.com/

8. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
This is fabric
going through
a singeing
machine

9. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
Onto de-sizing…
SINGEING DE-SIZING SCOURING BLEACHING MERCERIZING
PRE-TREATMENT

10. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
The reason for de-sizing because during the spinning
and weaving process, the fabric goes through sizing.
SIZING is when
SIZE is applied to
the fabric to protect
it from the abrasive
action of the loom.

11. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
WHAT IS SIZE?
Natural sizing agents
are mostly based on
starch and starch-
derivatives. There
are also synthetic
sizing agents such as
modified polyesters.
close-up of starch under
electron microscope

12. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
De-sizing is the removal of sizing
agents from the fabric using
enzymes, acid, oxidative agents,
etc. Enzymatic de-sizing is the
most common.

13. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
Irrespective of what kind of de-sizing, the
process includes:
Impregnation of fabric with
1 de-sizing agent
Allowing the de-sizing agent to
2 solubilize or degrade the size
Washing out the degradation
3 products

14. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
WASH OUT
EXAMPLE OF A DE-SIZING PROCESS: ENZYMES
F AB
RIC
+ ENZYMES
FOR EXAMPLE, CELLULASE, AN
ENZYME, BREAKS DOWN STARCH
Thanks to Prof. Michal Vik for all the information on de-sizing (from:
http://www.ft.tul.cz/depart/ktc/dokumenty/pte/2PTE%20Desizing.pdf)

15. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
Now we will talk about scouring…
SINGEING DE-SIZING SCOURING BLEACHING MERCERIZING
PRE-TREATMENT

16. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
SCOURING is the treatment of textile materials in
aqueous or other solutions in order to remove:
SIZING INORGANIC
DEGRADATION PECTINS SUBSTNACES
PRODUCTS
ALUMINIUM FATS
SIZES
AND IRON OXIDES AND WAXES

17. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
SCOURING can be carried out as a separate
step of the process OR in combination with
other treatments (usually bleaching or desizing)
on all kind of substrates (fiber, woven fibers,
knitted fibers).
Thanks to Dr. Schönberger and Dr. Schäfer from Best Available
Techniques in Textile Industry for information on scouring

18. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
EXAMPLE OF SCOURING PROCESS:
ALKALI,
AB
RIC
+ WETTING AGENTS,
ETC.
F
Thanks to Dr. Schönberger and Dr. Schäfer from Best Available
Techniques in Textile Industry for information on scouring

19. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
SINGEING DE-SIZING SCOURING BLEACHING MERCERIZING
PRE-TREATMENT

20. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
Bleaching increasing the whiteness of the
substrates, this is important for un-dyed fabrics
as well for fabrics dyed in light shades or with
a high brilliance.
Bleached products are usually treated with
hypochlorite or peroxide. Peroxide is more
commonly used for cotton whereas
hypochlorite is used for linen.

21. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
This is fabric
coming out of
a scouring
and bleaching
machine

22. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
SINGEING DE-SIZING SCOURING BLEACHING MERCERIZING
PRE-TREATMENT

23. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
Mercerizing is the treatment of cotton and
cotton blends with strong alkali under
tension.
Let’s see what it looks like…

24. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
ALKALI TREATING THE FABRIC
N
T ENSIO
NDER
FA BRIC U

25. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
Mercerizing is possible before and after a lot of steps
in the dyeing and finishing process.
For example:
• on greige goods
• after desizing
• after de-sizing and scouring
• after bleaching
• after dyeing

26. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
MERCERIZING CAN:
IMPROVE DYESTUFF ABSORPTION
INCREASE TENSILE STRENGTH
MAKE A RESISTANT LUSTER
IMPROVE DIMENSIONAL STABILITY

27. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
All the steps of the pre-treatment process can
take place in something like this:
This is a continuous dyeing machine.
Graphic from:
http://www.ineris.fr/ippc/sites/default/interactive/bref_text/breftext/a
nglais/bref/BREF_tex_gb55.html

28. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
Now that we have looked at all the basic
components of the pre-treatment process, let’s
see what a pre-treatment process might look
like for various substrates.

29. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
GREIGE
PREPARATION
SINGEING
For cotton and
CAN BE
cotton-based fabrics, COMPLETED
the pre-treatment DE-SIZING IN ONE-BATH
DYEING
process might look
like this…
MERCERIZING
SCOURING

30. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
GREIGE
PREPARATION
CIRCULAR
SINGEING
For knitted cotton
fabrics, the pre-
treatment process SCOURING CAN BE
might look like COMPLETED
IN ONE-BATH
this… BLEACHING DYEING
ALKALI MILLING
AND
MERCERIZING

31. 2. THE DYEING AND FINISHING PROCESS
A. PRE-TREATMENT
QUALITIES:
RELATIVELY CLEAN
SYNTHETIC FIBERS
FEW IMPURITIES
IN PRE-TREATMENT:
GENERALLY DO NOT BLEACH
WARM TEMPERATURE FOR
PRE-TREATMENT
(except for very white or
bright colored fibers)