Wool

STUDY ON
PROTEIN FIBER
Sunday, April 1, 2018
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Prepared By: SAGNIK GHOSH
B.TECH. In Textile Technology,GCETT,Serampore

THE NATURAL HAIR GROWTH OF CERTAIN ANIMALS
AND ARE COMPOSED OF PROTEIN.
PROTEIN-Any of a class of nitrogenous organic compounds
that consist of large molecules composed of one or more
long chains of amino acids and are an essential part of all
living organisms, especially as structural components of
body tissues such as muscle, hair etc.
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WOOL

WHERE ARE WOOL GET FROM???
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 Wool is the textile fiber obtained from sheep and
certain other animals, including cashmere from
goats, mohair from goats, other types of wool from
camelids.
 Wool has several qualities that distinguish it from
hair or fur: it is crimped, it is elastic, and it grows in
staples (clusters)

CHARACTERISTICS
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 The amount of crimp corresponds to the fineness of the wool fibers. A
fine wool like Merino may have up to 100 crimps per inch, while the
coarser wools like karakul may have as few as one or two. In contrast,
hair has little if any scale and no crimp, and little ability to bind into
yarn. On sheep, the hair part of the fleece is called kemp. The relative
amounts of kemp to wool vary from breed to breed and make some
fleeces more desirable for spinning, felting, or carding into batts for
quilts or other insulating products, including the famous tweed cloth of
Scotland.
 Wool fibers readily absorb moisture, but are not hollow. Wool can
absorb almost one-third of its own weight in water. Wool absorbs
sound like many other fabrics. It is generally a creamy white color,
although some breeds of sheep produce natural colors, such as
black, brown, silver, and random mixes.

QUALITY
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 Merino wool is typically 3–5 inches in length and is
very fine (between 12 and 24 microns).The finest
and most valuable wool comes from Merino hoggets.
Wool taken from sheep produced for meat is
typically more coarse, and has fibers 1.5 to 6 in (38
to 152 mm) in length. Damage or breaks in the wool
can occur if the sheep is stressed while it is growing
its fleece, resulting in a thin spot where the fleece is
likely to break.

•WOOL GREASE : 2 -25% OF GREASY WOOL WEIGHT
•SUINT : 2 -12% OF GREASY WOOL WEIGHT
•DIRT : 5 -45% OF GREASY WOOL WEIGHT
N O T E :
F I N E W O O L F R O M M AR I N O S H E E P US E D AP PAR E L , T Y P I C AL LY
C O N TAI N S 1 3 % W O O L G R E AS E .
C O AR S E R W O O L U S E D F O R C AR P E T S C O N TAI N S AN AV E R AG E O F
AB O U T 5 % G R E AS E .
THE NATURAL GREASE OF THE WOOL OF SHEEP, CONSIST
ING OF A MIXTURE OF FATTY
MATTER AND POTASSIUM SALTS, USED AS A SOURCE OF P
OTASH AND IN THE PREPARATION OF OINTMENTS.
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COMPOSITION OF RAW WOOL

KERATIN : 33%
GREASE : 28%
SUINT : 12%
IMPURITIES : 26%
MINERAL WATER : 01%
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CHEMICAL COMPOSITION OF WOOL FIBER

WOOL CONTAINS SOME SPECIAL PROTEIN LIKE KERATIN. MAIN
CHEMICAL COMPOSITION OF WOOL.
CARBON : 50%
HYDROGEN : 12%
OXYGEN : 10%
NITROGEN : 25%
SULFUR : 03%
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CHEMICAL COMPOSITON OF KERATIN

PHYSICAL STRUCTURE OF WOOL
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Description
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Cuticle
On the outside of the wool fiber is a protective layer of scales called cuticle cells.
They overlap like tiles on a roof. The exposed edges of the cells face away from the
root end so there’s more friction when you rub the fiber in one direction than the
other. This helps wool expel dirt and gives it the ability to felt. Wool felts when fibers
are aligned in opposite directions and they become entangled.
The scales have a waxy coating chemically bound to the surface. This stops water
penetrating the fiber but allows absorption of water vapor. This makes wool water-
repellent and resistant to water-based stains.
Cortex
The cortex – the internal cells - make up 90% of the fiber. There are 2 main types of
cortical cells – ortho-cortical and para-cortical. Each has a different chemical
composition. In finer fibers, these two types of cells form in two distinct halves. The
cells expand differently when they absorb moisture, making the fiber bend - this
creates the crimp in wool. In coarser fibers, the para-cortical and ortho-cortical cells
form more randomly so there’s less crimp.
Fiber crimp makes wool feel springy and provides insulation by trapping air.

Description
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Cortical cell
The cortical cells are surrounded and held together by a cell membrane complex,
acting similarly to mortar holding bricks together in a wall.
The cell membrane complex contains proteins and waxy lipids and runs through
the whole fiber. The molecules in this region have fairly weak intermolecular
bonds, which can break down when exposed to continued abrasion and strong
chemicals.
The cell membrane complex allows easy uptake of dye molecules.
Macro-fibril
Inside the cortical cells are long filaments called macro-fibrils. These are made up
of bundles of even finer filaments called micro-fibrils, which are surrounded by a
matrix region.
Matrix
The matrix consists of high sulphur proteins. This makes wool absorbent because
sulphur atoms attract water molecules. Wool can absorb up to 30% of its weight in
water and can also absorb and retain large amounts of dye. This region is also
responsible for wool’s fire-resistance and anti-static properties.

Description
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Micro-fibril
Within the matrix area, there are embedded smaller units called micro-fibrils. The
micro-fibrils in the matrix are rather like the steel rods embedded in reinforced
concrete to give strength and flexibility. The micro-fibrils contain pairs of twisted
molecular chains.
Twisted molecular chain and helical coil
Within the twisted molecular chains are protein chains that are coiled in a helical
shape much like a spring. This structure is stiffened by hydrogen bonds and
disulphide bonds within the protein chain. They link each coil of the helix, helping
to prevent it stretching. The helical coil – the smallest part of the fiber gives wool
its flexibility, elasticity and resilience, which helps wool fabric keep its shape and
remain wrinkle-free in use.

CHEMICAL STRUCTURE OF WOOL
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IN ADDITION TO CARBON, HYDROGEN, OXYGEN AND
NITROGEN IT ALSO CONTAINS SULPHUR. THE AMINO -
ACIDS PRESENT IN WOOL ARE MAINLY BULKY, WHILE
SILK HAS CHIEFLY SMALL AMINO-ACIDS. DUE TO THIS
WOOL IS RELATIVELY AMORPHOUS. THE POLYMER
SYSTEM OF WOOL IS HIGHLY AMORPHOUS THAT IS 75%
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PHYSICAL PROPERTIES OF WOOL

PHYSICAL PROPERTIES OF WOOL
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 Color : The color of wool fiber could be white, near white, brown and black.
 Tensile strength : The T.S of wool in dry condition is 1-1.7 and in wet condition 0.8-
1.6
 Elongation at break : Standard elongation is 25-35% & 25-50% in wet condition.
 Elastic Recovery : Good.
 Specific Gravity : 1.3-1.32
 Moisture Regain : Standard 16-18%
 Resiliency : Excellent.
 Luster : Luster of course fiber is higher than fine fiber.
 Effect of Heat : wool becomes weak of heat. It softness when heated or treated with
boiling water for long time. At 130 degree celsius it decomposes and chars at 300
degree celsius. Does not continue to burn when it is removed from a flame.
 Effect of Sun Light : The main chemical components of wool decomposes under the
action of sun light. The sulphur in wool is converted into H2SO4. The fibers become
discolored and develop a harsh feel.

CHEMICAL PROPERTIES OF WOOL
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 Effect of acids : Concentrated acids damage it since they hydrolyze
the salt linkages and hydrogen bonds. Dilute acids do not affect it.
 Effect of alkali : It easily dissolves in alkaline solutions. Alkalis
hydrolyze the disulphide bonds; hydrogen bonds and salt linkages of
wool and cause the polymers to separate from each other, which is
looked as dissolution of the fiber. Hydrolysis of the peptide bonds of
wool polymers lead to polymer fragmentation and total destruction of
the strand. Prolonged exposure to alkalis causes hydrolysis of the
peptide bonds of wool polymers lead to polymer fragmentation and total
destruction of the fiber.
 Effect of bleach : Chlorine bleach is ordinary harmful to the wool.
KMnO4, Na2O2 are utilized for bleaching.

CHEMICAL PROPERTIES OF WOOL
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 Effect of Organic solvent: Wool doesn’t affect in organic solvents.
 Effect of Insects: Wool affected by insects.
 Effect of Micro Organism: It affected by mildew if it remains wet for
long time.
 Dyeing Ability: wool fiber could be dyed by basic dye, direct dye and
acid dye.

DFE PROPERTIES OF WOOL FIBRE
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 Wool felts because of the serrated surface of its
fibres which is formed by the overlapping epithelial
cells or scales (as shown in fig.).
Because of this serrated structure, less
friction will result if the fibre moves in a
rootward direction than if it moves in a
tipward direction. This difference in surface friction
between the two directions is known as the
directional frictional effect, abbreviated to DFE.

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 The various forms/combinations of DFE, that can
occur in wool fibres can be illustrated in the figure
below :
DFE PROPERTIES OF WOOL FIBRE

GEOGRAPHICAL DISTRIBUTION OF MAIN WOOL PRODUCING COUNTRIES
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24%
15%
13%8%
3%
2%
3%
32%
Australia China
New Zealand CIS
Argentina South Africa
Uruguay Others
48%
26%
8%
7%
5%
6%
Europe North America
Asia south Africa
Africa Oceania

 AU S T R AL I A : 2 5 % O F G L O B AL W O O L
 C H I N A: 1 8 %
 U N I T E D S TAT E S : 1 7 %
 N E W Z E AL AN D : 11 %
 AR G E N T I N A : 3 %
 T U R K E Y: 2 %
 I R AN : 2 %
 U N I T E D K I N G D O M : 2 %
 I N D I A: 2 %
 S U D AN : 2 %
 S O U T H AF R I C A : 1 %
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Sunday, April 1, 2018 25
1. CHINA
2. United kingdom
3. India
4. Germany
5. Italy
6. Japan
7. U.S
8. Czech republic
9. France
10. Greece
11. Hong Kong
12. Malaysia
13. Mexico
14. Nepal
15. Netherland
16. Spain
17. South Korea
18. Taiwan
19. Thailand
20. Turkey

 Australia.
New Zealand
Europe
Argentina
South Africa
Uruguay
The United States
Russian Federation
Iran
Morocco
India

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Shearing should happen at least once a year and as
early in spring as possible
 Sheep can be sheared prior to lambing to make it
easier, or they can be crutched out
 Shearing is a specialized skill and its hard work, but
anyone can learn how to shear
 Fun facts:
• Sheep shearers can shear a sheep in under a minute
• World recorders: sheep: 38 secs lamb: 19.8 secs
• Bioclip: Australian wool harvest technology, a way of removing
fleece without shearing
Invented in 1994, inject sheep with
 Special hormone ,then wrap them in tight hairnets,
 Three weeks later the fleece can be peeled off

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 Different Types of Wool :
Fine wool
 Medium Wool.
 Long breeds wool
 Cross breeds wool
 Carpet wool
 Classification of Wool By flees :
 Normal wool.--------------- ( 6 to 8 years of sheep )
 Hagget wool ----------------( 12 to 14 years of sheep)
 Pulled wool -----------------( 15-16 years of sheep)
 Cotty wool ------------------( very low quality sheep)
 Tag lock wool --------------( Discolor sheep )
 Dead wool ----------------- ( Nearly dead sheep)
 Weather wool --------------( Collecting after one collection)

 Wool is classed according to characteristics-
 Range: breed – half breed, crossbred, merino;
 age - lamb, hogget, ewe;
 category - bellies, pieces, fleece;
 quality – micron, yield, length;
 grade - color, vegetable matter, tenderness, other faults.
 Classification of Wool
The quality of wool fibers produced is based on the
breeding conditions, the weather, food, general care etc.
For example, excessive moisture dries out natural grease.
Similarly the cold weather produces harder and heavier
fibers. The wool could be classified in two different ways:
By sheep from which it is obtained
 By fleece
 Classification by Sheep

The wool is classified according to the sheep from which it is
sheared as given below:
 Merino Wool: Merino sheep originated in Spain yields the
best quality wool. These fibers are strong, fine and elastic
fiber which is relatively short, ranging from 1 to 5 inches
(25 – 125 mm).
 Among the different wool fibers, merino wool has the
greatest amount of crimp and has maximum number of
scales. These two factors contribute to its superior warmth
and spinning qualities.
 Merino is used for the best types of wool clothing.
 Class – Two Wool: This class of sheep originates from
England, Scotland, Ireland and Wales. The fibers are
comparatively strong, fine, and elastic and range from 2 to
8 inches (50 – 200mm) in length.
 They have a large number of scales per inch and have good
crimp.

 Class – Three Wool: This class of sheep originates
from United Kingdom. The fibers are coarser and
have fewer scales and less crimp when compared to
earlier varieties of wool fibers and are about 4 to 18
inches long.
 They are smoother, and are more lustrous.
 These wool are less elastic and resilient.
 They are of good quality, used for clothing.
 Class – Four Wool: This class is a group of mongrel
sheep sometimes referred to as half-breed. The
fibers are about 1 to 16 inches (25 – 400 mm) long,
are coarse and hair like, and have relatively few
scales and little crimp.
 The fibers are smoother and more lustrous.
 This wool is less desirable, with the least elasticity
and strength. It is used mainly for carpets, rugs, and
inexpensive low-grade clothing.

 Classification by Fleece
Shearing, is the process by which the woolen fleece of a sheep is
removed. Sheep are generally shorn of their fleeces in the spring, but
the time of shearing varies in different parts of the world. Sheep are
not washed before shearing. They are sometimes dipped into an
antiseptic bath as prescribed by law. The classification by fleece is as
follows:
Lamb’s Wool: The fleece obtained by shearing the lamb of six to eight
months old for the first time is known as lamb’s wool. It is also referred
to as fleece wool, or first clip. As the fiber has not been cut, it has a
natural, tapered end that gives it a softer feel.
Hogget Wool: Hogget wool is the one obtained from sheep about
twelve to fourteen months old that have not been previously shorn.
The fiber is fine, soft, resilient, and mature, and has tapered ends.
These are primarily used for warp yarns.
Wether Wool: Wether wool is the one obtained from the sheep older
than fourteen months. The shearing is not done for the first time and in
fact these fleeces are obtained after the first shearing. These fleeces
contain much soil and dirt.

WOOL CLASSING
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Pulled Wool: Pulled wool is taken from animals originally slaughtered for
meat. The wool is pulled from the pelt of the slaughtered sheep using
various chemicals. The fibers of pulled wool are of low quality and produce
a low-grade cloth.
Dead Wool: This is the wool obtained from the sheep that have died of
age or accidentally killed. This type of wool fiber known should not be
confused for pulled wool. Dead wool fiber is decidedly inferior in grade; it is
used in low-grade cloth.
Cotty Wool: This type of wool is obtained from the sheep that are exposed
to severe weather. As discussed; the severe weather conditions hamper
the qualities of the fleece obtained. The cotty wool is of a poor grade and is
hard and brittle.
Tag locks: The torn, ragged, or discolored parts of a fleece are known as
tag locks. These are usually sold separately as an inferior grade of wool.

Sorting the Merino fleece:
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 The merino sheep produces the finest of all wools, and the fleece
has been finely graded by Dr. Bowman in this manner –
Shoulders: The wools grown on these parts are commonly the best
in the fleece, being specially strong and long in staple, soft in
texture and uniform in character.
 Sides: Same as shoulders.
 Lower part of back: This is also wool of good, sound quality,
resembling in staple that obtained from the shoulders and sides, but
not so soft and fine in fibre.
 Loin and back: The staple here is comparatively shorter and the
hair not so fine, but the wool on the whole is of a true character. In
some cases, however, it is rather tender.
 Upper parts of legs: Wool from these parts is of a moderate length
but coarse in fibre, and is disposed to hang in loose, open locks. It
is generally sound, but liable to contain some vegetable matter.

Sorting the Merino fleece
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 Upper portion of neck: The staple of the wool clipped from this part of the neck is
wholly of an inferior quality, being faulty and irregular in growth, as well as full of thorns,
twigs, grass, and other matters.
 Central part of back: This wool closely resembles that obtained from the loins and
back, and is rather tender.
 Belly: This is the wool grown on the under parts of the sheep, between the fore and
hind legs. It is short, dirty and poor in quality, and somewhat tender.
 Root of tail: Fibre coarse, short and glossy, and very often the wool is mixed with
kemps or dead hairs.
 Lower parts of legs: Most of the wool grown on these parts is dirty, greasy, and rough,
the staple lacking curliness and the fibre fineness. It is usually full of burrs and
vegetable matters.
 Head: The wools from the part is stiff, straight, coarse, mixed with fodder and kempy.
 Throat: Same as head.
 Chest: Same as head.
 Shins: The wool from the shins is short, straight and stiff and of small textile value

 Wool fabric is used for all kinds of clothing,
couch covers, bedspreads, toilet covers,
tablecloths and more.
 Boots
 Carpet
 Blankets
 Sweaters
 Coats
 Seat covers etc.

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