Wool

 Wool is the fiber derived from the hair of animals of the Caprinae family, principally Sheep, but the hair of certain species of other mammals such as goats, llamas and rabbits may also be called wool.  Wool has two qualities that distinguish it from hair or fur: it has scales which overlap like shingles on a roof and it is crimped; in some fleeces the wool fibers have more than 20 bends per inch.

 In the thirteenth century, the wool trade was the economic engine of the Low Countries and of Central Italy; by the end of the following century Italy predominated.  Due to decreasing demand with increased use of synthetic fibers, wool production is much less than what it was in the past.  The collapse in the price of wool began in late 1966 with a 40% drop; with occasional interruptions, the price has tended down.

• Sheep were one of the first animals domesticated by humans. These sheep looked very different from modern animals. They had a long hair-like outer guard layer with a more downy insulation layer underneath resembling what we think of as wool. They shed this coat in the spring. Primitive people collected the fiber finding it to be of great use, learned to spin. Thus the wool industry was born. • The first sheep were brought to the North American continent in 1493 on the second voyage of Columbus

• New England was the first area to establish a spinning and weaving industry. Initially begun in homes, later in small factories, it continued to grow. Eventually the first water powered textile factories were established in 1788. • The industry was greatly boosted during the Civil War by a great demand for wool to make soldier's uniforms. Breeders use imported Merino sheep to improve native stock to help meet the demand

Today

• Wool is 5% of the world's textile industry. • Most of our domestic breeds produce 45 times more wool than sheep initially brought to the United States greatly due to the influence of the Merino. • All domestic wool produced finds use in a variety of products. However, because of defects, contamination, and other quality problems, it is of lower value than some imported wool.

• Mills rely on imported wool to maintain operation (about 76%). • The mills require higher quality fiber to maximize production due to modern methods and equipment.

Other Wool Producing Countries Australia, Argentina, New Zealand, Russia, Republic of South Africa, Great Britain, China, and U.S.A.

The quality of wool is determined by the breeding, Climate, food, general care and health of the sheep. • • • • •

Cold weather produced a hard and heavy fiber Poor or insufficient food retards growth. It has soft resiliency power and it is also used to make rugs and blankets. The chief wool producing countries are Australia, U.S.S.R., New Zealand, Argentina, South-Africa and the United States (U.S.A.). The chief constituent of wool fiber is a protein substance called ‘Keratin’ and it is the only fiber which contains ‘Sulphur’.

CLASSIFICATIONS FOR WOOL

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Wool may be classified by two types: 1. Classification by sheep 2. Classification by fleece

 Classification by Sheep: There are over 200 grades of wool producing sheep. – Merino Wool:- Produced from Merino Sheep and the fibres are very fine, strong and elastic. – Class two Wools:- Originated in Scotland, Ireland and Wales. – Class three Wools:- Originated in the UK, generally are less elastic and resilient. – Class four Wools:- Obtained from Mongrel Sheep, are coarse and hairlike.

 Classification by Fleece (Based on the shearing of the fleece):– Lamb’s Wool: About 6-8 to months. – Hogget Wool: About 12-14 months. – Wether Wool: Any fleece clipped after the first shearing of sheep. – Pulled Wool: The shearing done by a chemical depilatory like lime before it is slaughtered for meet. – Dead Wool: The shearing is done over the dead sheep – Cotty Wool: The wool obtained from any sheep of severe weather condition.

1. CLASSIFICATION BY SHEEP

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1. CLASS I WOOL (OR) MERINO WOOL

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Merino sheep of Spain produce the best quality wool which is strong, fine elastic and has good working properties.

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It has the greatest amount of crimp of all wool fibers and has a maximum number of scales to give maximum warmth and spinning qualities. Spain is the only country which produced fine wool known as ‘merino wool’.

2. CLASS II WOOL

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It is obtained from the sheep from England, Scotland, Ireland and Wales.

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It is 2 to 8 inches in length, has a large number of scales per inch and has good crimp.

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The fibers are strong, fine , elastic and have good working properties.

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It is not as good as merino wool, but nevertheless it is very good quality wool.

3. CLASS III WOOL

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This class of sheep originated in United Kingdom.

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The fibers are 4 to 8 inches long, are coarser and have fewer scales and less crimp than Merino Wool and class II wool.

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They are smoother and have more luster.

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They are nevertheless of good enough quality to be used for clothing.

They are less elastic and resilient.

4. CLASS IV WOOL

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This class is actually a group of Mongrel sheep sometimes referred to as half-breeds.

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The fibers are 1 to 16 inches long are coarse and hair like, have relatively few scales and little crimp and therefore smoother and more lustrous.

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It has least elasticity and strength and used mainly for carpets, rugs and inexpensive low-grade clothing.

STRUCTURE OF WOOL 

The Cortex of the wool fibre is composed of two distinct sections, Ortho cortex and Para cortex.

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The Microscopic structure of wool has following parts: Cuticle Macro Fibril Micro Fibril Proto Fibril Wool Polymer

Structure • Epicuticle- thin outer membrane covering the cuticle • Cuticle- protective layer of overlapping flattened cells called scales • Cortex- major component of wool fiber, inner layer • Medulla- the central core found primarily in medium and coarse wool

PHYSICAL PROPOERTIES • The physical properties of the wool refers to the strength, thermal nature, etc. • The various physical properties are: Tenacity Elastic and Plastic Nature Hydroscopic Nature Heat of Wetting Thermal Properties

•TENACITY Wool is comparatively a weak fiber. The low Tensile strength of wool is due to the relatively few Hydrogen Bonds that are formed. When Wool absorbs moisture, the water molecules gradually force enough polymers apart cause a significant no. of hydrogen molecules to break. Breakage and Hydrolysis of these Inter Polymer forces of attraction are apparent as swelling of fiber and result in further loss of tenacity, when wool is wet.

• Elastic and Plastic Nature Wool has very good Elastic recovery and excellent Resiliency (ability to withstand elastic force). This is because of Helical structure of arrangement of monomer or due to the helical polymeric configuration of wool.

• HYDROSCOPIC NATURE Wool is a very Absorbent fiber due to the Amorphous nature of polymer system. In relatively dry weather, wool develops static electricity. This is because there are not enough water molecules in the polymeric system to dissipate any static electricity which is being developed.

• HEAT OF WETTING Wool is renowned for its ability to give off small but steady amount of heat while absorbing moisture. This is known as Heat of Wetting. It is considered to be due to energy given off by the collision between water molecules and the groups in the wool polymer system. This friction is severe and thereby liberates energy. Thus, wearer feels slightly warm when the wool fabric absorbs moisture.

• Crimp • Caused by the unique chemical and physical properties of wool. The fiber tends to bend and turn in to a resilient 3 dimensional structure. It holds in air to insulate the wearer. This property make wool naturally elastic and resilient causing rapid wrinkle recovery, durability, bulk, loft, warmth, and resistance to abrasion. • Water Absorbency • Wool can absorb up to 30% of its weight in moisture without feeling damp or clammy. This makes wool good for all climates since it aids in the body's cooling mechanisms to keep moisture away from the skin.

• Resistance to Fire • Wool contains moisture in every fiber allowing it to resist flame without any additional chemical treatment. The wool will just char and self extinguish. • Dyeability • Wool absorbs many dyes deeply, uniformly, and directly without the use of chemicals. This characteristic allows wool to achieve very beautiful and rich colors when dyed.

• Durability • The flexibility of wool makes it very durable. A single wool fiber can be bent back on itself more than 20,000 times without breaking. Compare this to the only 3,000 times of cotton and 2,000 times of silk. Its elasticity makes it very resistant to tearing. Wool also has an outer film making it resistant to abrasion. • Resilience • Wool fiber can be stretched up to 50% of its length when dry and up to 30% of its length when wet without breaking It will return to its original length when released.

CHEMICAL PROPERTIES • EFFECT OF ACIDS AND ALKALIS Wool is resistant to Acids than to Alkalis because alkalis hydrolysis the Peptide group( -[CONH]- ) Wool is not at all resistant to alkalis. Wool, when submerged into high quantity of high concentrations of acids, gets weakened.

• EFFECT OF BLEACHES  Wool is treated with Reducing Bleaches such as  Sodium sulphide

 Sodium Bisulphide

which converts the color producing component of the fabric to colorless compound.  After this, Oxidizing bleach such as Hydrogen Peroxide is applied which converts compounds into water soluble compounds.  After this, the wool fibre is rinsed off and a permanent bleach is obtained. The dyes used in wool are : Acid dyes, Mordant dyes, Reactive dyes, etc.

 The hair of the sheep is trimmed first.  The raw wool or newly sheared wool called grease wool because it contains the natural oil of the sheep.  Sorting & Grinding:– Wool sorting is done by skilled workers who are experts in distinguishing by touch and sight. – Determined by type, length, fineness, elasticity and strength.

 Garnetting:– Separating the used and unused materials to a fibrous mass by picking and shredding. – Fibres are then put into a dilute solution of Sulphuric Acid to remove vegetable fibres is called Carbonizing.

 Scouring:– Raw wool is scoured by washing it in a solution of soap, warm water and soda ash or any other alkali. – This removes the grease and oil in wool and makes it absorbent to dye.

 Drying:– Wool is not allowed to dry completely, 12-16% of moisture is left over.  Oiling:– Wool is treated with oil to lubricate it and to keep it from becoming brittle.  Blending:– Wool of different grades may be blended in this stage.

 Carding:– Fibres are passed through rollers covered with thousands of wire teeth to orient the fibres parallel. – This separates the woolen yarns and worsted yarns.  Gilling and Combing:– The gilling process removes the short staple and straightens the fibres. – Combing operation removes the shorter fibres and places long fibres parallel to each other.

CARDING PROCESS

 Drawing:– Makes the sliver compact and thin by doubling and redoubling the wool fibre.

 Roving:– It is a process to hold the thin slubbers intact. – The fiber passes between the rollers, over the coarse wire teeth of the first card clothing, and over progressively finer toothed card clothing. – the fiber that leaves the machine are in the form of untwisted ropes known as ‘ROVINGS’.

WOOL- After ROVING

 Spinning:– Roved wool is drawn out and twisted into yarn. – Woolen yarns are spun on mule spinning machine. – Worsted yarns are spun on any kind of spinning machines.

SPUN WOOL YARNS

MACHINE SPINNING

SPINNING WHEEL

FINISHES USED • • •

Fulling Crabbing Decating: It includes two processes

4. Dry Decating 5. Wet Decating

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London shrinking

Wool Blends Wool is blended with a wide variety of fibres. Wool and Cotton Wool is blended with cotton in various ratios. The properties of the yarns and fabrics will be affected by the proportions of the fibres blended. Wool contributes warmth, resilience, abrasion resistance, and drapability. Cotton adds strength and reduces the cost of yarn and fabric. Both fibres are absorbent and can be blended to make a comfortable, durable fabric with a nice hand. • Wool and Linen Wool is sometimes blended with linen. Linen may be used in such a blend which is stronger than a pure wool fabric, but is more resilient and drapable than a pure linen fabric.

GRADES OF WOOL In order for wool to be sold in International Trade, methods of expressing grades for raw wool have been devised. On the World Market, grade is expressed by a Number System. The Finer the wool, the Higher the number. Comparative Grading Systems •

Fine

80s,70s, 64s

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Half-blood

62s, 60s, 58s

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Three-eighths blood

56s

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Quarter-blood

50s, 48s

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Low-quarter blood

46s

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Common

44s

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Braid

40s, 36s

SOURCES OF WOOL  Large wool producing and exporting nations are:

• Australia ( 50s- 80s) •

New Zealand ( 40s – 60s and carpet grade)

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South Africa ( 60s – 70s and carpet grade)

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Argentina ( 40s – 60s, 64s and carpet grade)

 Countries contributing to greatest amount of carpet wool to world market are: Argentina, India, Pakistan, New Zealand, Syria, Iraq and Iran.

BENEFITS OF WOOL • • • • • • •

Resists Wrinkles Retains Shape Resists Soiling Resists Flames Wool is Durable Wool is comfortable in all seasons Repels Moisture

APPLICATIONS OF WOOL Wool is used in the manufacture of various Products like:

• Boots • Carpet • Blankets • Sweaters • Coats • Seat covers • Bed sheets • Cushion covers • Curtains

MANUFACTURING PROCESS OF WOOL (in detail) • • • • • • • • • • • • • •

1. Preparation 2. Sorting and Grading 3. Garneting 4. Scouring 5. Carbonizing 6. Drying 7. Oiling 8. Dyeing 9. Blending 10.Carding 11.Gilling and Combing 12.Drawing 13.Roving 14.Spinning

1. PREPARATION

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Fleeces vary from 6 to 18 pounds (3-8Kg) in weight and provides 3 lbs (1.5Kg) of scoured wool.

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Wool is sorted and graded according to the quality, then trimmed, rolled up, tied and packed in sacks weighing about 225-350 lbs (100-160Kg).

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Superior wool comes from the sides and shoulders of sheep where it is longer, finer and softer and it is treated as one fleece.

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Wool from the head, chest, belly and shanks is treated as a second fleece.

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Then wool reaches the mill in bags.

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The raw wool or newly sheared wool is called grease wool as it contains the natural oil of the sheep.

2. SORTING AND GRADING

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Wool sorting is done by expert skilled workers who distinguish the different qualities by touch and sight.

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Twenty different grades are obtained from one fleece.

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Each grade is determined by type, strength, length, fineness, elasticity and strength.

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The grading system on the world market is based upon the British numbering system which relates the fineness or diameter of wool, etc.

3. GARNETING

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Recycled wool fibers are obtained by separately reducing the unused and used materials to a fibrous mass by a picking and shredding process called garneting.

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The fibers are then put through a dilute solution of sulphuric acid or hydrochloric acid which destroys any vegetable fiber that may be contained in the raw stock. This process is known as ‘Carbonizing’ and the resultant wool fibers are called “extracts”.

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The new staple ranges from ¼ to 11/2 inch in length.

4. SCOURING • •

“A thorough washing of raw wool in an alkaline solution is called scouring.” The scouring machine contains warm water, soap and a mild solution of soda-ash or other alkali and is equipped with automatic rakes which stir the wool. Rollers between the vats squeeze out the water. Valuable by products are obtained from the spent liquors in the scouring of wool. The most important by product is lanolin which is largely used in manufacture of cosmetics, adhesive plasters, disinfectants, ointments,etc.

5. CARBONIZING

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Fibers are put in Hydrosulphuric acid or Hydrochloric acid solution to destroy vegetable substance.

•If the wool still contains and vegetable substance after scouring, it is put through carbonizing process which burns out the foreign matter.

6. DRYING

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Wool is not allowed to become absolutely dry. Usually about 1216% of the moisture is left in the wool for further handling.

7. OILING

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Wool becomes unmanageable after scouring, the fiber is usually treated with various oils, including animal, vegetable and mineral or a blend of these to keep it from becoming brittle and to lubricate(oil) it for the spinning operation.

8. DYEING

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If wool is to be dyed in the raw stock, it is dyed at this stage whereas wool fabrics are piecedyed, yarn skin dyed and some are top-dyed.

9. BLENDING

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Wool of different grades may be blended or mixed at this stage.

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Inferior grade of wool mixed with better grades of wool or a small amount of cotton is blended with a raw wool and a greater amount of twist is increase the strength in the fabric.

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Manmade fibers such as nylon, polyester or acrylic may be blended with wool and the wool helps in contribution of warmth, absorbency, drape and handling.

10. CARDING

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The carding process introduces the classification of woolen yarns and worsted yarns.

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At this point, of manufacturing process, it should be decided weather wool fiber is to be made into a woolen or a worsted product, because manufacturing of woolen and worsted is different.

11. GILLING AND COMBING

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The carded wool which is to be made into worsted yarn is put through gilling and combing operations.

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The gilling process removes the shorter fibers (called as combing noils and of 1-4 inches in length) and places the longer fibers (tops) as parallel as possible and further cleans the fibers by removing any remaining loose impurities.

•Combing noils (shorter fibers) are used for ordinary and less expensive fabrics and tops (longer fibers) for manufacturing worsted fabrics as gabardine, whipcord, serge and convert and produce fabrics with good colour, feel and strength,

12. DRAWING

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It is done only to worsted yarns. It is an advanced operation which doubles and redoubles slivers of wool fibers. The process draws and twists the fibers and makes the slivers more compact and thin.

13. ROVING

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It is the final stage before spinning. It is a slight twisting operation to hold the thin slubbers (fibers) intact.

14.SPINNING

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Here the wool roving is drawn out and twisted into yarn.

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Woolen yarns are spun on mule spinning machine. Worsted yarns are spun on mule, ring, cap or flyer kind of spinning.

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Two different systems to spin worsted yarns – is English System and French System:

Difference between Woolen and Worsted Yarns WOOLENS 1.Fibers are short (2”length) 2. Woolen yarns are only carded, less twisted and hence weak in strength. 3. Woolen fabrics are woven with plain weave and sometimes twill weave. Weaving is not compact and fabric is not durable or strong. 4.Woolen fabrics are soft, fuzzy, thick and warm but not durable. 5. Woolen can be easily adulterated and napping finish is given to produce soft surface. 6. Less expensive than worsted. 8. -These fibers are more warmer than worsted. -It has no luster and is less durable. -The napped surface tends to catch and hold dirt but stains can be easily removed.

WORSTED 1. Fibers are long (2-8 inches) 2. Worsted yarns are carded and combed, highly twisted and more strong. 3. Worsted fabrics are woven chiefly with twill weave and weaving construction is close and compact and as such more strong fabric. 4. Worsted fabrics are flat, rough, harsh when worn next to the skin, but more durable. 5. Worsted can not be easily adulterated as it has a hard finish on the surface. 6. More costlier or expensive than woolens. 7. -It wrinkles less than woolen, holds creases and shape, and become shiny with use -They re amore durable and more resistant to

CUSHION COVERS

SWEATERS

SHAWLS

CURTAINS

SOCKS

BED SHEETS

CARPETS