Yaa Basic Concept Of Wool: Production To Application

Basic Concept of Wool: Production to Application

Md. Nazmul Huda Sohag
Dept. of Textile Engineering
TMSS Engineering College (Afflicted yesteryear Rajshahi University)
Email: sohagnazmul124@gmail.com

Wool:
Wool is a natural fiber which nosotros obtain from the fleece of domesticated sheep. It is a natural, protein, multicellular, staple fiber. Wool is a lineament fiber in addition to thus it is unique in addition to valuable inwards its properties. In a sheep nether the layer of coarse pilus fibers, in that place is an undercoat of finer hairs, much to a greater extent than delicate. This inner insulating layer has given us the textile fiber known equally wool.

is a natural fiber which nosotros obtain from the fleece of domesticated sheep Yaa Basic Concept of Wool: Production to Application

Fig: Wool fiber

Wool producing countries:
Wool is to a greater extent than oft than non produces inwards cool condition. The next are the wool producing country:

Spain,
New Zealand
France
Australia
Argentina
Brazil
U.S.A
South Africa
India
U.K
Uruguay
Turkey etc.

Composition of wool:

Keratin -------------------------- 33%
Dirt ------------------------------ 26%
Suint ---------------------------- 28%
Fat ------------------------------- 12%
Mineral materials -------------- 1%

Composition of Keratin:

C ------------------- 50%
O ------------------- 22-25%
due north ------------------- 16-17%
H ------------------- 7%
south ------------------- 3-4%

Classification of wool:

Classification yesteryear sheep quality:
On the footing of sheep in that place are iv types of wool. These classifications depending on fineness in addition to length. These are:

Class I, Merino Wool,
Class II Wool,
Class III Wool,
Class IV Wool.

1) Class I, Merino Wool:
It is mainly make inwards Australia, New Zealand, South Africa, South America, Europe (Germany, France, Spain)

The staple length of:

Features:

Fiber is fine in addition to strong.
Highly elastic
Good working properties,
Greatest sum of crimp,
The scale of unit of measurement length is real high,
Maximum no. of scales almost 8000 to the inch.

2) Class II Wool:
This cast of wool mainly produces inwards England, Scotland, in addition to Ireland. It qualities are almost same to Class-I Wool precisely length is niggling precisely higher.

Staple length = 2// - 8//

Features:

This lineament is non goodness equally merino wool,
It has large no. of scale per inch.
Uses mainly inwards hosiery in addition to knitting; suitable for coating in addition to wearing apparel

3) Class-III Wool:
Origin of this wool is United Kingdom of Great Britain in addition to Northern Ireland

Staple length = 4// - 8//

Features:

Coarse in addition to less elastic,
Have fewer scale,
Have less crimp in addition to thus merino in addition to Class-II Wools.
Used for clothing.

4) Class-IV Wool: (Cross-breed Wool)
This cast is genuinely referred equally cross breed wool.

Staple length = 1// - 16//

Features:

Coarse in addition to pilus like.
Have relatively fewer scales in addition to real niggling crimp.
Smoother in addition to convey to a greater extent than lusture.
Used for carpet, rugs in addition to depression grades fabrics.

Classification yesteryear fleece:
These are of vii types:

Lambs wool,
Cotty wool,
Hogget wool,
Taglocks.
Wether wool,
Pulled wool,
Dead wool,

1) Lambs wool:
Refers to the commencement fleece sheared from a lamb almost six to 8 months old.

2) Hogget wool:
Refers to the commencement fleece come upwards from a sheep almost 12 to xiv months old.

3) Wether wool:
Any fleece clipped afterward the commencement shearing is called wether wool.

4) Pulled wool:
When the sheep are slaughtered for meal, their wool is delineate from the pelt yesteryear the role of chemicals.

5) Dead wool:
Wool has been covered from the sheep that convey died on the attain or convey been accidently killed.

6) Cotty wool:
Sheep that are exposed to severe atmospheric condition conditions or lack of nourishment yield a wool is called cotty wool.

7) Taglocks:
The torn, ragged or discoloured parts of a fleece are known equally taglocks.

Classification yesteryear quality:
According to lineament in that place are 5 types of wool.

These are:

Fine wool,
Medium wool,
Long wool,
Cross breed,
Carpet or mixed wool.

1) Fine wool:

Length = 6// - 7//
Source = entirely the merino sheep produces this sort of fleece.
Producing sheep = the regulation merino families of today are the Spanish, French, Australian, American, South African.

2) Medium wool:

Length = 4// - 6//
Source = It is proced from the firbst breed of sheep. Great England make the largest per centum of this type wool.
Producing sheep = South down, Hampshire, Dorest, Succex.

3) Long wool:

Length = 3//- 4//
Source = Breeds of largest sheep.
Producing sheep = Lincoin, Cots wold, Leicester, Romney marsh.

4) Cross breed wool:

Length = 4// - 6//
Source = Medium wool
Producing sheep = Columbia, Panama, Romledale, Polwarth & Targhee.

5) Carpet or mixed wool:

Length = 2//- 4//
Source = Primitive sheep (lower quality)
Producing = Mainly inwards Asiatic countries, America, Australian.

The manufacturing procedure of wool:

Shearing:
Wool is a natural, protein, multicellular, staple fiber which may live sheared cast the living animal, domesticated sheep or pulled from the shroud afterward the creature has been slaughtered for its meat. The sheared wool is called fleece or loving cup wool. Sheep are sheared i time or twice a year. This shearing procedure is done yesteryear an practiced shearer, who tin clip equally many equally 100 to 200 sheep a day.

The sheep is sheared yesteryear early on saltation in addition to the fleece removed inwards i slice yesteryear practiced shares.

Sorting:
Wool sorting is done yesteryear skilled workers who sorts according to fineness, length in addition to some times forcefulness of fibers.

Scouring:
Following sorting, the wool is scouring. This involves washing inwards warm soapy H2O several times. It moves the natural grease inwards the fiber in addition to saint dirt in addition to dust.

Oiling:
The wool fiber is treated yesteryear diverse crude including animal, vegetable in addition to mineral because of unmanageable.

Garneting:
The shredding procedure of recycled wool fiber is called garneting.

Carbonizing:
After garneting, the wool fibers are position through a dilute solution of HCl or H2SO4 which destroys whatever vegetable fibers. This procedure is known equally carbonizing

A morphological diagram of a wool fiber:

Fig: Morphological diagram of a wool fiber

The micro construction of wool consists of 3 primary components:

The cuticle
Cortex
Fibrils.

1) The cuticle:
The cuticle is the layer of overlapping epithelial cells surrounding the wool fiber. It consists of the epicuticle, exocuticle in addition to endocuticle.

The epicuticle is the outermost layer which covers the wool fiber. It is entirely few molecules thick in addition to composed of a H2O repellent, wax-like substance.

The overlapping epithelial cells cast the exocuticle. An epithelial jail mobile telephone is almost 1

long in addition to 36 wide. The epithelial cells are largely responsible for the felting shrinkage of untreated wool textile materials.

The endocuticle is an intermediate cementing layer bonding the epitheial cells to the cortex of the wool fiber.

2) Cortex:
The cortex of wool fiber forms almost 90% of the fiber volume. It consists of countless long, spindle-shaped cells. If a specially selected dye is applied to the fiber in addition to the fiber cross-section examined, the ortho in addition to para cortex travel apparent. The ortho cortex absorbs to a greater extent than dye than para cortex. The cortex of the wool fiber is composed of ii distinct sections.

a) Ortho-cortex, b) Para-cortex.

The ortho in addition to para cortex spiral closed to i another, along the length of the wool fibre.

3) Fibril:
The cortical cells of the wool fiber consists of a release of macro fibrils each almost 100-200 nm inwards diameter. The macro fibrils are held together yesteryear a poly peptide matrix. Each macro fibrils consists of hundreds of micro fibrils, each almost 5nm inwards diameter. Each micro fibril consists of 11 photos fibrils almost 500nm inwards length in addition to 2nm inwards diameter. Finally, each photograph fibril consists of 3 wool polymers, which also spiral closed to each other.

Why ortho-cortex absorbs to a greater extent than dye than the para-cortex?
The ortho-cortex absorbs to a greater extent than dye than the para-cortex. The argue for this dissimilar staining is the dissimilar composition of the para-cortex in addition to the ortho-cortex. The chemic composition of the para-cortical cells shows a higher cystine (cystine is a sulpher containing amino acid, capable of forming disulphide cross-links) content than the ortho-cortical cells.

Since in that place is a greater sum of cystine inwards the para cortical cells, a greater release of disulphide cross links be inwards the para-cortex. This increased cross-linking tends towards greater chemic stability resulting inwards less dye absorption.

Why wool is fine to wear?
Due to helical configuration of ortho in addition to para cortex, wool fiber has a smoothness, flexibility, elasticity in addition to to a greater extent than durability. So nosotros tin state that wool fiber has higher resiliency properties. That is why wool fiber is fine to wear.

General construction of poly peptide fiber:
The wool polymer is linear, keratin polymer, amongst some real brusque side groups in addition to it commonly has a helical configuration. The repeating unit of measurement of the wool polymer is the amino acid which has the next full general formula.

(The steps inwards the formation of the wool polymer are non known. So the amino acid is considered the repeating unit of measurement of wool. As a result, it is non possible to create upwards one's heed the extent or marker of polymerization for wool.)

Amino acids are linked to each other yesteryear the peptide bond (i.e. --CO--NH--) to the wool polymer. The peptide bond is identical amongst the amide bond of the nylon polymer. The wool polymer is composed of 20 amino acids, precisely entirely a full general formula tin live given for the wool polymer.

It is known that, inwards general, the amino acids arginine, crystine in addition to glutamic acid flora at to the lowest degree one-third of the wool polymer. Wool is composed inwards 20 release of amino acid in addition to silk is composed inwards sixteen release of amino acid.

Polymer system:
The wool polymer is linear keratin polymer amongst some real brusque side groups in addition to it commonly has a helical configuration. Influenza A virus subtype H5N1 wool polymer is almost 140nm long in addition to almost 1nm thick 25-30% crystalline. It has peptide bond (-CONH-), H-bond, cystine linkage (disulphide bond).

Keratin:
Keratin is an amphoteric inwardness i.e. reacts equally both acids in addition to bases. Keratin is made upwards of 5 chemic elements-carbon, hydrogen, oxygen, nitrogen in addition to sulpher.

α-Keratin:
When wool polymer is inwards its relaxed province in addition to thus it is spiral/helical. This spiral or helical configuration of wool polymer is called

-Keratin.

β-Keratin:
When wool polymer is stretched, in addition to thus it unfolds. The unfolded configuration of the wool polymer is called

-Keratin.

Why wool fiber is like shooting fish in a barrel to dye?
Wool is a poly peptide fiber which has to a greater extent than amorphous part than crystalline region. So dye molecules tin easily travel into to the amorphous part of the fiber. Moreover wool is to a greater extent than absorbent inwards nature. So, wool is like shooting fish in a barrel to dye.

Difference betwixt ortho in addition to para cortex/ mutual properties of ortho & para cortex:

Ortho Cortex	Para Cortex
1. Lower density.	1. Higher density.
2. More absorbent.	2. Lower absorbent.
3. Tends to live inwards the outer sides.	3. Tends to live inwards the insides.
4. Contains lower cystine content.	4. Contains higher cystine content.
5. Elastic & Flexible.	5. Stable in addition to stiff in addition to tends to tighten the spiral.

Macro construction of wool:
The wool fiber is a crimp, fine to thick, regular fiber. As the diameter of wool fiber increases, the release of crimps per unit of measurement length decreases. Influenza A virus subtype H5N1 unmarried wool fiber is rod similar in addition to tapers from the root terminate to its tip.

1. Length: 5-35cm

2. Diameter:

Fine 14
Coarse 45

3. Length width ration:

Fine short- 2500:1
Long coarse- 75:1

4. Color:
Off white, low-cal cream.

5. Crimp:
10 per centimeter

Physical Properties of Wool:

01. Tenacity:
8.8-15 CN/Tex (1.0-1.7gm/den) inwards dry out province in addition to 7-14 CN/Tex (0.8-1.6gm/den) inwards wet.

02. Elongation:
25-35% nether criterion conditions in addition to 25-50% when wet.

03. Elastic properties:
It has an elastic recovery of 99% at 2% extension in addition to 63% at 20% extension.

04. Specific Gravity of wool:
1.32 in addition to thus fabrics experience lighter than cellulose.

05. Resiliency:
Higher in addition to thus resist wrinkling.

06. Hygroscopisity:
Higher

07. Cross section:
Oval to roughly circular.

08. Appearance in addition to colour:
Appearance depends on colour, long in addition to polish fiber characterized yesteryear ii features. Sometimes microscopically shows night inwards the middle. This kemp, which are pilus similar character. By selective breeding kemp tin live minimized.

Chemical properties of Wool:

01. Effect of moisture:
Wool absorbs wet to a greater extent than whatever other fiber in addition to yield upwards readily to the atmosphere. Under ordinary conditions wool volition concur 16-18% of it weight of moisture. Wool loses almost 40% of its forcefulness in addition to silk loses almost 15% inwards wet condition.

02. Effect of acids:
Wool is attacked yesteryear hot concentrated sulphuric acid in addition to decomposes completely. It is inwards full general resistant to other mineral acids of all strength. Even at high temperature, though nitric acid tends to campaign harm yesteryear oxidation. Dilute acids are used for removing cotton fiber from the mixture of ii fibers.

03. Effect of alkalis:
The chemic nature of wool keratin is such that it is peculiarly sensitive to alkaline metal substances. Wool volition dissolve inwards caustic soda solutions that would convey niggling consequence on cotton. The scouring in addition to processing of wool is carried out nether conditions depression alkalinity (NaOH, NaCO3). Ammonium Carbonate, borax in addition to sodium phosphate are mild alkalis that convey a minimum consequence on wool.

04. Effect of organic solvents:
Wool has a goodness resistance to dry out cleaning in addition to other mutual agents.

05. Effect of bleaches:
Wool fibrion is attacked yesteryear oxidizing agents or bleaches such equally H2O2, NaOCl, calcium hypochlorite Ca(OCl)2 , KMnO4, K2Cr2O7, O3, NaCl. Wool becomes yellowish inwards sodium hypochloride (NaOCl) in addition to dissolve. It is less harmed yesteryear reducing agents or bleaches such equally ZnO, SnCl2, SO2, H2S in addition to FeSO4.

06. Effect of sunlight:
The keratin of wool decomposes nether the activity of sunlight. The sulphur inwards wool is converted into sulphuric acid thus the fiber becomes discolored in addition to develops a harsh feel. It losses its forcefulness in addition to the dyeing properties are affected. Tends to yellowish white or tardily color or surface polymer degraded yesteryear ultraviolet radiation.

Thermal properties of Wool:
Wool becomes weak in addition to losses its softness when heated at the temperature of boiling H2O for long periods of time. At 1300C, it decomposes in addition to turns to yellowish in addition to it damages at 3000C. Wool doesn’t travel on to burn downwardly when it is removed from a flame. Do non burns readily is self extinguishing, convey aroma of burning pilus in addition to convey a dark crushable ash.

Biological properties of Wool:
Wool is attacked yesteryear moth-grubs in addition to yesteryear other insects. Wool has a misfortunate resistance to mildews in addition to bacteria in addition to it is non advisable to travel out for equally good long inwards a damp condition.

End uses of wool: