WOOL

Wool

Wool and hair fiber are the natural hair of

certain animals and are composed of protein.

Protein consists of complex organic

compounds containing amino acids.

The chief wool producing countries are UK,

Australia, New Zealand, Argentina, South

Africa and United States.

Wool

The wool fiber is obtained from sheep.

The breeding of sheep and the production of

wool fibers are more costly processes than the

cultivation of plant fibers.

Consequently wool fibers are more expensive

than cotton and linen.

Hair fibers have all qualities of wool.

Longitudinal view

Cross sectional view

Wool

The sources of wool fiber are:

1. Camel hair

2. Mohair ( obtained from Angora goat )

3. Cashmere ( obtained from Cashmere goat )

4. Llama ( obtained from camel like animal )

5. Alpaca ( obtained from domesticated

animal that resembles llama.

CashmereAngora

Wool

Classification of Wool:

The sheep may be classified into four types.

1. Merino Wool:

Merino wool ( obtained from Merino sheep) is

considered as best quality wool.

Fiber is strong, fine and elastic.

Merino is used in the best types of wool

clothing.

WoolThe staple of Merino wool is relatively short ( 25-125 mm ). The staple is relatively ranging from 1-5 inch.

The varieties of merino sheep are chiefly found in Spain, New Zealand, South America, South Africa and Australia.

Wool

b. Class-Two Wool:

This class of sheep is originated in England,

Scotland, Ireland and Wales.

The staple fiber is relatively longer than

Merino ( 50- 200 mm). It is 2-8 inches.

The fibers are strong, fine and elastic but not

as strong, fine and elastic as merino. It has

scales and crimps but not as more and goods

as merino wool.

Wool

c. Class three wools:

This class of sheep originated in the United Kingdom.

The fiber are about 4 to 18 inches long ( 100-455 mm ).

These are coarser and have less crimps and scales.

As a result they are smoother and have more luster.

Wool

d. Class- four wools:

This class of wools are 25-400 mm long (1-16

inch), coarser and hair like having less scales

and little crimp.

Therefore, these wools are smoother and

more lustrous having less strength and

elasticity.

Wool

Classification by fleece:

Fleece is the coat of wool shorn from the sheep at a time.

1. Lamb’s wool:

The first fleece sheared from a lamb about 6-8 months old is known as lamb’s wool or sometimes referred to as fleece wool or first clip. Lamb’s wool is immature and not strongas fully developed wool of same sheep.

Wool

2. Hoggest wool:

Hoggest wool come from sheep 12 to 14 months old that have not been previously shorn. The fiber is soft and fine.

3. Wether Wool:

Any fleece clipped after the first shearing is called wether wool.

This wool is usually taken from a sheep older than 14 months.

Wool

4. Pulled wool:

When sheep is slaughtered for meat, their

root are pulled. Such wool is called pulled

wool fiber and is inferior for two reasons.

1. Sheep that are raised for meat generally do

not have a good quality of wool.

2. The roots of fibers are damaged by

chemicals and tension exerted in pulling.

Wool

5. Dead wool:

The wool recovered from a sheep died or

killed accidently.

6. Cotty wool:

Sheep that are exposed to severe weather

conditions or lack of nourishment yield a wool

that is hard and brittle.

http://biotechlearn.org.nz/focus_stories/wool_innovations/wool_processing_fleece_to_fabric

• Scouring

if we didn’t wash our hair for a year, imagine what

our hair would be like??????

“Sheep has that same issue”

The scouring process – Just like washing,

Because the sheep picks up contaminants such as dirt

and also releases sweat and grease, so that has to be

removed.

• Gilling

Gilling is a process of aligning the wool fibres so

they are parallel to one another. This is done

using a coarse comb. At this stage, the sliver still

contains particles of vegetable matter as well as

short fibres.

• CombingThere’s usually small particles of vegetable

matter – seeds and leaf– picked up by the

sheep.

So combing removes vegetables matters. It also

removes the short fibres, because short fibres

are hard to control in the yarn. It’s much easier

for the spinner to organise longer fibres.

Growth of Wool Fiber:

The wool fibers grows up in groups of 5-80

hairs .

There are about 10,000 to 22,000 scales per

square inch.

The average rate of growth of wool fiber is 1

inch in two month.

Quality of Wool

The quality of wool varies with;

�Breed of sheep.

�Conditions under which it has lived.

The quality and price of raw wool depends on;

�Fineness

�Length

�Strength

�Purity

�Color

Fineness - fiber diameter

Thicker Thinner

Fine$$$$

CrossbredMedium

LongCoarse

Grade refers to the relative diameter of the wool fibers (fineness).

< 17µ> 40 µ

Average Fiber Diameter ( Microns) Wool Grades

Under 17.70 Finer than 80’s

17.70-19.14 80’s

19.15-20.59 70’s

20.60-22.04 64’s

22.05-23.49 62’s

23.50-24.94 60’s

24.95- 26.39 58’s

26.40-27.84 56’s

27.85- 28.29 54’s

29.30-30.99 50’s

31.00-32.69 48’s

32.70-34.39 46’s

34.40-36.19 44’s

36.20-38.09 40’s

38.10-40.20 36’s

Over 40.20 Coarser than 36’s

Types of wool Yarn

Wool is spun into two types of yarn.

1. Woolen yarn:

Woolen yarn is thick, and fibers in woolen

yarn are held loosely and subjected to only

limited twist during spinning.

These yarn are woven into thick bulkier

material.

2. Worsted yarn:

Worsted yarns are finer, smoother and

stronger than woolen yarns.

The fibers in worsted yarn are twisted strongly

to form fine and strong yarn.

These yarns are woven into fine dresses.

Properties of Wool

Tensile strength:

Wool has tensile strength of 17000-29000 lbs

per square inch.

Elongation:

Wool has an elongation at break 25-35 %

under standard conditions of testing.

Elastic properties:

Wool is an elastic fiber. It has elastic recovery

of 99 % at 2% extension and 63 % at 20%

extension.

Specific gravity:

It has specific gravity of 1.32.

Effect of moisture:

Moisture regain of wool is 16 %.

Effect of heat:

At 130 degree centigrade, it decomposes and

turns yellow.

Wool becomes weak and loses its softness

when heated to temperature of boiling water

for long period of time.

Effect of age:

Wool shows little deterioration with age when

stored carefully.

Effect of sunlight:

Wool is weakened by prolonged exposure to

sunlight. The wool becomes discolored and

develops a harsh feel.

Effect of Acids:

Wool is attacked by hot sulphuric acid and

decomposes completely.

Dilute acids are used for removing impurities

without damaging the wool fibers.

Effect of alkalis:

Unlike cotton, structure of wool is sensitive of

alkaline substances.

Wool will be dissolved by caustic soda

solutions. The scouring and bleaching of wool

is carried under low alkaline solution like

sodium phosphate and ammonium carbonate

which have minimum effect on wool.

Effect of insects:

The proteins of wool is a modified form of

meat so it can be easily attacked by moth

grubs and other insects.

Micro organisms:

Wool has a good resistance to mildews and

bacteria.

Advantages of Wool fiber

• Wool is Natural

�Renewable

�Sustainable

�Biodegradable

�Energy efficient

• Wool is Safe

�Flame resistant

�UV protection

�Static electricity reduction

�High thermal resistance

• Wool is Healthy

�Breathable

�Humidity control

�Low allergy

�Toxic chemical

absorption

�Sound reduction

Applications of wool

� Apparels

� Technical Textiles

� Interior Textiles

http://www.iwto.org/wool/wool-applications/

Apparel:Suits, jackets, pullovers, coats, sportswear, skiwear, scarves, gloves, socks, hats,active wear, children's wear, waterproof fabrics, casual wear, shoes, formal wear, hand knitting wool, uniforms.

Interior Textiles:Carpets, duvets, mattresses, pillows, blankets, upholstery, tapestries, lamps, rugs, futons, bedspreads, tablecloths, wall coverings, sofas.

Technical Textiles:Aircraft interiors, thermal insulation, sound insulation, sound vibration control, roof insulation, filtration, fire proof wear, police uniforms, military uniforms, air conditioning, bandages, second skin injury prevention, piano felts, wool filters for dust chemical odours, billiard cloths, automotive composites, tennis balls