The document discusses various finishing processes used for wool fabrics, including methods to impart permanent set, control shrinkage, and moth proofing. It describes three main methods of permanent set - decatising, crabbing, and potting. Decatising uses steam under pressure to set the fibers, while crabbing uses heat and moisture. Potting involves boiling rolled wool fabrics to achieve a high degree of set. The document also covers concepts of shrinkage in wool and methods to control it, including landon shrinkage and compressive shrinkage treatments.

1. FINISHING OF WOOL

2. CONTENTS
 INTRODUCTION
 CONCEPT BEHIND ALL PROCESS
 METHODS OF PERMANENT SET
 SHRINKAGE
 MOTH PROOFING
 ANTI PILLING
 CONCLUSION

3. INTRODUCTION
 Wool is a protein based natural fiber.
 Woolen fabrics are soft and light weight in
which the fibers are arranged at random in
yarn.
 Wool can absorb more moisture than any
other natural fiber without feeling wet and
also exhibits valuable warmth properties.
 These fibers posses excellent elasticity and
draping properties.

4. FACTORS RESPONSIBLE IN
WOOL FINISHING
1. Heat
2. Moisture
3. Pressure

5. WOOL FINISHES
 The methods of finishing wool are more complex
than other textiles.
 The major use is made on two properties of
wool:
 a. The ability to acquire permanent set
 b. The felting phenomenon.
 Both of these depends on heat , moisture ,
pressure.
 For milling of wool , the most responsible factor
is pressure.

6. PERMANENT SETTING
 Setting-
Bringing of textile material to the specified
configuration by suitable methods is called setting.
 Purpose of set –
Woolen fabrics have remarkable property of
elasticity means it can be stretched or contracted
from its original length depending upon the
conditions in which the stress or strain is applied .
So to avoid any kind of distortions in the shape of
woolen fabrics while manufacturing process their
structure is stabalized by the relaxation of stress &
setting in permanent manner .

7. Continue…
 Degrees of set –
1)-Cohesive set –disappears from fabric when
tension is released in cold water.
2)-Temporary set- persists in fabric when
tension is released in cold water.
3)-Permanent set - remain in the fabric even
after the tension is released in boiling water.

8. PURPOSE OF SETTING
To avoid any kind of distortions to dimensions of
woolen fabrics during manufacturing process.
 PERMANENT SET-
When woolen fabrics are stretched in cold water
they are highly elastic but when it is stretched in hot
water for certain time in alkaline medium it is then
permanently set & does not recover in cold water
even after removal of tension.
Permanent set can be studied in two mechanism-
1. Physical mechanism
2. Chemical mechanism

9. PHYSICAL MECHANISM
 Permanent setting takes place in two steps-
1).Break down of cross linkages
2).Rebuilding of new cross linkages
 When woolen fabrics are stretched, the polypeptide
chains uncoils and the hydrolytic breakdown takes
place .
 If the strain in NaOH solution is applied to woolen
fabrics is less than 15 minutes then super-
contraction takes place means wool contract from
less than its original length but if the strain is applied
for more than 15 minutes then extension in length of
woolen fabrics takes place means they are
permanently set.

10. Continue…
 The physical mechanism can be explained by
the graph .
 Explanation of graph-
 For 40 % extension in length of woolen fabrics in
NaOH solution ,if extension is for less then 15
minutes then graph is moving downwards
means that super-contraction takes place as
new cross links are not build up.
 But on other hand when this extension is for
more than 15 minutes then graph moves upward
means extension in length occurs and new cross
links are formed in stretched condition and

11. Continue…

12. Continue…
 The physical mechanism can be explained by the
graph .
 Explanation of graph-
1. For 40 % extension in length of woolen fabrics in
NaOH solution ,if extension is for less then 15
minutes then graph is moving downwards means
that super-contraction takes place as new cross
links are not build up.
2. But on other hand when this extension is for more
than 15 minutes then graph moves upward means
extension in length occurs and new cross links are
formed in stretched condition and permanent
setting occurs.

13. Chemical mechanism-
 The first reaction that takes place is hydrolysis of
cystine linkage.
R-S-S-R + H2O  R-SH + RS-OH ……..(i)
 The reaction occurs at pH 9.2
 Next the rebuilding of the new linkages is by reaction
between hydrolysis product and salt.
RS-OH + R’NH2  R-S-NH-R’ + H2O ………(ii)
 When we use sodium bisulphite at alkaline pH then
the side products are different but the main product
formed is same.
R-S-S-R + NHSO3  R-S-Na + R-S-SO3H ………..(i)
R-S-SO3H + R’-NH2  R-S-NH-R’ + H2SO3 …………(ii)

14. CONCEPTS BEHIND ALL THE
PROCESS
 In finishing of woolen fabric, three major terms are to
be taken into consideration:
1).Shrinkage
2).Permanent set
3).Milling

15. CONCEPT OF SHRINKAGE
 When the wool fiber first enters the spinning
line, the tension starts to act onto the fiber.
This tension leads to the extension of each
wool fibers.
 These leads to the breakage of temporary
cross links in between the polymeric chains
and reformation of new links at its new
position.

16. Continue…
 After the loom stage, when the tension ( applied
to hold the fabric) is released, the tension in
each wool fiber also gets released.
 Due to this, each polymeric chain tries to return
back to their original positions.
 Thus the extended fiber again acquire their
original configuration.
 This leads to the shrinkage of fibers and thus
the distortions in fabric.

17. CONCEPT OF PERMANENT SET
 To rectify this problem of shrinkage, one
thing can be done.
 If, by some means, we freeze the polymeric
chains in their new positions after the
applications of tension, then it will not return
to its original positions.
 Then we say that the fabric has been set in
its new configurations.
 This is known as permanent set.
(conti..)

18. WOOL FINISHES
 In permanent set, we use few auxillaries to
do this job of freezing the polymeric chains.
 These chemicals not only freeze the
polymeric chains but also tighten these new
links.
 It is done by breaking of cystine linkages and
their reformation as discussed in permanent
set process.

19. CONCEPT OF MILLING
 It is also one of the major processes related
to woolen finish.
Difference b/w milling & felting:
 Milling : it is the process.
 Felting : it is the phenomena.

21. FELTING
 Wool fibers have scales on their surface that provide
friction among themselves.
 Wool fibers have two ends- root end & tip end.
 Wool fibers have a tendency to always move ‘towards
their root ends’.
 So when pressure is applied, two things can happen-
i)- either two adjacent fibers are facing with their root
ends with each other
ii)- or, two tip ends are facing each other.
(conti…)

22. In the first case
Upon application of pressure two adjacent wool
fibers tend to come closer to each other and
thus an overall compact structure is obtained,
known as felt.
In the 2nd case
two adjacent fibers try to move apart and extend
the fabric; however lack of rigidity prevents this,
so the fiber loops and forms further
entanglements with other fibers as milling
proceeds.
(conti…)

23. Continue…
 So, in this way milling occurs.
 The necessary pressure is applied with
various machines such as stock milling or
rotary milling.
 Also presence of any solvent (acid, alkali or
soap) facilitates this milling effects, which has
been described earlier.

25. METHODS OF PERMANENT
SETTING
 It can be mainly done by 3 ways:
1. Decatising
2. Crabbing
3. Potting

26. DECATISING
.

27. INTRODUCTION
 Also known as Crabbing & Blowing ;Decatising is a
process of making a permanent textile finish on a
cloth ,so that it does not shrink during garment
making .
 The word decatising come from French word
Decatir ,which means to remove the ‘’Cati’’ or finish
of the wool
 Though used mainly for wool ,the term is also
applied to processes performed on other fabric such
as cotton ,linen or polyester.

28. DEFINITION
 The core idea is to set the fabric in such a way that it
can handle the finishing process.
 By the process ,heat as well as moisture are applied
along the length of fabric in order to help it attain a
permanent state.
 The property of interest is the ability of fabric to undergo
stress by employing decatising one aims to take care of
shrinkage by giving it a permanent dimension so that
further process does not change shape

29. OBJECTIVE
 Shrink free finish
 Smooth and wrinkle finish
 Enhance natural luster of fabric
 Permanent setting of woollen fabric

30. DECATISING
 To set woollen material at various stages of the
production of woollen fabric and garment.
 The function of setting is to relax the various stress
build up in the material.
 This is a stress relaxation process .
 This is the process can be done during the spinning
and weaving and to stabilize the fibre in new and
desired configuration.

31. PROCESS
 Chemical changes taking during setting of wool
involves Thiol di sulphide exchange.
 Wool fibre contains small quantity of Thiol group (-SH)
which can be increase by reaction of wool i.e., Di
sulphide bond(-S-S).
 The interchange reaction and hydrogen bond
rearrangement are important in wool setting.
 The set is stabilized by the rearrangement of
hydrogen and disulphide bond in the stress relax
state.

32. METHODS OF DECATISING
 Pressure Decatising
 Continuous Pressure Decatising

33. PRESSURE DECATISING
• In this process ,the woollen fabric is wound under
tension on a perforated beam whose perforation are
covered by a fine cotton cloth.
• A heavy end cloth is wound on top of the roll to give
protection and apply pressure to the outer layers of
the woollen cloth.
• The beam with the batch of cloth wound on it is then
placed in a pressure vessel which is closed and
evacuated by vacuum.

34. Continue..
 Steam is blown through the beam (from inside to
outside) for 2-3 minutes under pressure .
 Steam blown into a closed vessel creats pressure(as
in a pressure cooker).
 Vacuum helps steam to penetrate the fabric.
 During steaming the beam is kept rotating.

35.  After 3 minutes the direction of steam is reversed to
pass through the beam from outside to in side by
suction.
 In this process the fabric is treated only once as there
is no need to treat the cloth twice.
 It gives uniform results and permanent finish.
Continue..

36. CONTINUOUS PRESSURE
DECATISING
 The latest method of setting woollen fabrics is the
continuous pressure decatizing method.
 This can be done in mather and platt vaporloc
pressure vessel.
 The process is carried out in continuous working
vaporloc vessel in which the fabric is in open width is
subjected to steam under pressure for 1 min at 140 C.
 The machine is provided with a seal to allow the fabric
to enter and leave the autoclave under pressure and
the process is continuous.

37. Continue..
 In this chamber repeated intermittent pressure
is applied to the fabric by nip rollers and smooth
surfaced impermeable glass fibre.
 A special type of wrapper used to cover the
face side of the fabric to give it a smooth handle
and elegant appearance.

38. 2. CRABBING-
 This treatment is imparted to light weight open weave,
woolen fabrics & fabrics containing highly twisted yarn
to eliminated distortion like crows foot , cockling ,
uneven shrinkage so that the fabric does not get
distorted during the subsequent operation of scouring
& dyeing.
 This treatment is based on the combined effect of
moisture & heat on the fabric.

39. Continue..

40. 3. POTTING-
 It is also called roll boiling.
 This treatment is given to the high quality woolen fabrics
to give soft handle & a higher degree of setting.

41. PROCESS
 In this treatment the cloth is wound on
perforated iron roller under uniform tension &
no crease is allowed during winding . Roller is
wrapped with piece of cloth then woolen fabric
is wrapped then over woolen fabric one more
cotton wrapped and tied this system with cord
to avoid slipping.
 Now place the roller vertically in tank filled with
cold water.

42. Continue…
 Then the temperature of tank is gradually
raised to boil and roller is kept in boiling tank
for the 4-5 hr. it is then taken-out and water is
drained out.
 After this process cloth is unwound & wound
on another cylinder to repeat this process for
two side potting.
 Now the cloth is cooled gradually

44. BEAMING
 Beaming is regarded as a mild form of potting and
generally used to remove crimp or other marks
which have generated during the scouring , milling or
dyeing .
 The goods are run through the hot water and
stretched in the weft direction by an expander roller
or tenter crab before wound over wooden roller or
beam.
 Now this wrapped fabric beam is wounded with
wrapper cotton and tied with the cord and goods is
allow to cool over a period of 12 to 48 hr.
 For the light weight woolens , a steam may use
instead of hot water.

46. SHRINKAGE
 Introduction:
Reduction in the length or width of a fiber,
yarn or fabric is known as shrinkage.

47. CAUSES OF SHRINKAGE IN
WOOLEN FABRICS
 When wool goods are washed, there is a
considerable reduction in area, which is
commonly termed shrinkage.
 It occurs because:
1. The relaxation of extension brought about
during the manufacturing processes( referred
as ‘relaxation shrinkage’), and
2. The felting of the wool fibers (referred as
‘milling shrinkage’).

48. CAUSES OF MILLING SHRINKAGE
 Broadly speaking, two main features in
wool account for milling shrinkage:
1. the scale structures which produces
unidirectional travel, and
2. the property of wool being stretched but
recovering from extension.

51. METHODS
 Landon shrinkage:
This process is probably best known treatment
involving the use of cold water, as originally carried out.
1. Modern method: Impregnating the wrapper with water
on a damping m/c in usual manner by rubber bowls,
then winding the wrapper, together with wool cloth to be
damped, on to roller; m/c is then reversed and the
damped cloth is cuttled or plaited & allowed to stand.
2. Standing time ---- 12 hours
3. Dried in old-fashioned room or on festoon m/c.
4. After drying, the cloth is pressed, book-old fashion
1. Time ----- 10-12 hours
2. Pressure ----- about 3000 lbs

52. STEAMING
This is the simplest method. In this process,
we have to blow hot steam into the fabric
until it is thoroughly wet after.

53. COMPRESSIVE SHRINKAGE
1. Woolen or worsted material is nipped twice
while travelling at different speeds, the area
b/w the two nips being confined in a closed
space so that buckling cannot occur
2. When compressed fabric emerges from the
apparatus, the natural resilience of the wool
causes it to lengthen directly the
compressive force is removed, although it
remains much shorter than it was originally.

54. Continue…
1. Lengthening may be controlled to a certain
extent by steaming the cloth in contracted
state immediately it emerges from the m/c;
2. Steaming pressure --- 5 lbs
3. Time --- 1 hour
4. Then cooling to impart necessary set.
5. Result : Fabric becomes heavier and denser;
elasticity increased
6. Only warp way felting is removed, not weft
way.

55. MOTH PROOFING
1. Mothproof finish is directed towards the garment fur
moth the anthrrmus, attunes beetle etc, which live as
textile parasites on keratin contains substances. To
protect wool form attack of moth many organic and
inorganic compounds have been used .
2. Inorganic compounds - chromium fluoride, sodium
silico fluoride, antimony fluoride and salts of
phosphotungstic acid, antimony tungstic acid,
molybdic acid.

56. Continue…
3. Organic compounds - Pentachloro phenol, DDT,
Dieldrin and Dinitro naphthol based acid dye (Mitin FF,
Eulan CN) 3. Modification of disulfide linkage (-CH2-S-
S-CH2-) in wool polymer into bis-thioether (-CH2-S-
CH2CH2-S-CH2-) linkage by ethylene bromide and
glyoxal.

57. ANTIPILLING
 Pill formation is a function of rubbing against the
fabric so pills are mostly found in garment areas
where rubbing is most prevalent, i.e. areas near
pockets, collars and cuffs. Pilling during wear can be
observed in both woven and knitted wool and blend
apparel and garments and while not causing failure
of the garment in the normal sense, reduces its
aesthetic appeal

58. Continue…
 Generally it is to be greater problem in blend
fabrics than in pure wool, because the high-
strength synthetic fibres anchor the pills to the
fabric surface preventing their removal during
wear .
 A number of processes have been shown to
improve the pilling performance of woollen
apparel fabrics for examples the degradative
anti-felting finishing (by chlorination) improves
the pilling performance of knitted fabric .

59. CONCLUSION
 As mentioned in the beginning the
basic idea behind the whole process is
to make the fabric ready for the
required purpose or its end use.
 To increase its dimensional stability
 To decrease the felting of wool