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Similar to processing Physical_and_Chemical_Properties_of_Wool (1).ppt
processing Physical_and_Chemical_Properties_of_Wool (1).ppt
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- 2. General Properties ofTrue Wool: • Elastic and hygroscopic (25 % of weight) • Inflammability: slower to burn, and on burning, it gives off a pungent odour and forms a bead when burning ceases • Retains warmth (insulator) • Devoid of stiff medulla and central core of hard cells. • Fine enough for production of soft pliable yarn. • Natural felting property Wool's scaling and crimp make it easier to spin and felt the
- 3. Physical properties ofWool Fleece Density- Number of fibers per unit area on skin. Fine wool breeds such as Marino has more fleece density than coarse wool breed. Diameter- Measured in micron to indicate wool fiber fineness. Fiber cross section-It is circle to oval Crimp-The waviness per cm in wool fiber which speaks of the qualitative fineness. Specific gravity-It is 1.304 in dry non-medullated wool.
- 4. Refractive index -Itvaries in between 1.553 to 1.555. Lusture – Ability of wool to reflect light. Wool with lustre, when dyed, has a brighter appearance than wool without lustre. Coarse wool with fewer scales has more lustre than fine wool because of smoothness of fibre Sheen or gloss. It depends on structure of fiber surface, size and straightness of the fiber. Electrical conductivity- wool is good insulator to current. Thermal conductivity-Wool does not support fire.
- 5. Moisture regain- Weightof water in wool as percentage of dry weight. R = W/D* 100 ; W= weight of water, D = Oven dry weight Moisture content- It denotes weight of water present in wool as percentage of total weight. M = W/W+ D *100 Moisture content of greasy wool is less than that of scoured wool. Coarse wool has more affinity to water. Moisture relation-The electrical properties varies with moisture content. Moisture swelling-It represents swelling in fiber diameter due to absorption of moisture.
- 6. Chemical properties ofWool Chemically wool is approximately 50 % carbon, 22 to 25 % oxygen, 16 to 17 % nitrogen, 7 % hydrogen and 3 to 4 %sulfur. Composed almost totally of amino acids Wool is described as 100% protein and is classified as an insoluble, sulfur containing protein called keratin. Wool becomes yellow if kept in warm humid places.
- 7. Action ofheat • Wool burns slowly and forms a porous brittle mass of carbon which emit disagreeable fume like that of smell of burning of hair or feather. • Wool fabrics become plastic in moist air at 100 0C but can be easily moulded in to shapes which are retained on cooling. • It gives up all moisture when heated to 100- 1500C and produces a rough harsh brittle substance with less strength. • Despite re-absorption potential of moisture original strength, softness and elasticity is not restored completely.
- 8. • Dry woolat higher temperature become discoloured and decomposes. • Keratin decomposes readily to ammonia at 130 0C. • Gases having sulfur are given off at still higher temperature. • Gases like ammonia, hydrogen, water, carbon dioxide, carbon monoxide and carbon are formed in absence of air at still further high temperature. Action of water • Wool is neither soluble in cold nor hot water. • Breaking up of wool macromolecules occur on continued boiling with water which causes decomposition. • Wool softens and losses strength on soaking in cold or hot water but drying restores it to some extent. • Wool acquires increased affinity for dyes on exposure to action of steam at high temperature.
- 9. Action ofacids • No harm occurs to wool in cold or boiling dilute solution of acids. • Wool absorbs the solution of acid and that is not removable by washing with water as amino group acts as site for holding acids in wool. • Wool acquires more affinity for acid dyes but decreases its basic dyes affinity when treated with an acid especially sulfuric acid. • Colour of wool become light yellow on treatment with nitric acid and this colour reaction is useful in identification of animal fibers. • Slow dissolution of wool occurs in concentrated inorganic acids.
- 10. Action ofalkalis • Wool is comparatively sensitive to alkalis. • Complete destruction or dissolution of wool occurs when boiled with 5% solution of caustic soda even for few minutes because amino group breaks as a result of hydrolysis. However, dilute solution of ammonia does not harm wool but concentrated solution at higher temperature harms wool. • Wool needs great care during laundering for prevention of fabric shrinkage. • Wool fabrics absorb and hold odour more than other fabrics which can be removed by controlled laundering but not effectively. • Wool garments contain more number of bacteria than any other garment from other textile fibers in similar use and dry cleaning kills 90% of such germs with elimination of health hazard.
- 11. Mechanical properties Wool fiberundergoes considerable strain in manufacturing process as carding, combing and spinning. The ultimate strength of the wool will achieved is influenced by: Poor nutrition cause tenderness and break in fibers. Photochemical action of light on very open type fleece on the back wool of animal weakens it. Breed and strength differences of wool fiber are associated with difference in diameter, on application of tension or constant rate of loading to a wool fiber in water or moisture. Extension of fiber proportional to load as per hooks. Moving up of “Easy Stretching Zone” from 30-100% extension in boiling water or steam owing to wet wool fiber being much easier to stretch than dry wool fibers.
- 12. • Complete recoveryof 30% stretched fiber due to reversibility of hydrogen bonding transformation in water. • Incomplete reversibility of fiber extension in post yield region of load extension curve due to breakage of disulfide bonds • Positioning of fibers made permanently with fixing fluid on woolen fabrics (sodium bisulphate solution, ammonium trioglycollate).
- 13. Speciality Fibre • Fromgoat and camel Goat Family- Angora goat- Mohair Cashmere goat- Pashmina fibers Common goat- Goat hair
- 14. Camel • Dromedary/Bactrian camel–produces camel hair
- 15. Llama family Guanaco-produces fiber Llama-Llama hair Vicuna- Vicuna wool Alpaca- Alpaca hair
- 16. Mohair • Long fibercovers of Angora goat originated in Asia Minor. • Angora goat - in province of Angora in Turkey • Elimination of Kemp fiber is an important factor for improvement of Angora goats. • More desirable and stronger than Kashmir • Fineness bearing with age. • Kid Mohair forms better fiber and yarn than advent mohair.
- 17. Physical Properties ofMohair • Clean yield- 81- 83% • Fibre diameter- 22.7- 23.3 micron • Staple length- 7.9- 8.2 cm • Medullation- 5.5- 6.2 • Kemp- 4.5- 7.6
- 18. Pashmina Fibre Softest,finest and costliest animal fiber known in the textile industry Produced by fine under coat of Capras hircus (Pashmina goat) originated in Asia Parent breed is the Kel of Kashmir and extend high mountainous region of Asia, Himalayan region and outer magnolia Colour- white or brown Diameter- 13 to 18 micron Length- 3-12 cm % Hair- 10- 40%
- 19. Pashmina • Obtain bycombing, clipping mohair, shearing per sheep. • Have cylindrical scale and longer than wool • Yield increases from 1-4th fleeces yield and declined there after. • Sub zero temperature induces production of pashmina fibers. • Male produces more pashmina than female • 3 items more insulating property than wool. • Short soft and non –medulated. • Weaker than mohair and wool. • Pashmina wears are less durable than woolen fibers.
- 20. PROCESSING OF WOOL •Wool shearing: - The process of removal of wool from sheep or harvesting of wool from the body of the sheep is known as shearing. • Shearing is strictly a seasonal job and can be performed any time except during winter. • The practice of shearing sheep is not uniform, which may vary according to agro-climatic condition of the region. • Sheep are normally sheared twice or thrice a year.
- 21. Methods of shearing 1.Hand shearing 2. Mechanical shearing by power operated shearing machines 3. Chemical shearing: The method of feeding sheep 24 mg Cyclophosphamide (CPA) @ per kg body weight of sheep. After 12 days of feeding of the chemical, wool is removed within 3 days starting from 12th day after drug administration.
- 22. 1. Tagging: -Tagging is a practice that improves the appearance of wool clip. It consists of removing the tags and dung locks especially in the sample obtained from hindquarters of the animal. 2. Wool grading or Wool classing:- The quality of wool differs in many respects as described in previously.
- 23. 3. Sorting: -Raw wool brought to the factory is sorted first as per the requirement. This is an advanced step requiring more skill and is different from classing or grading. 4. Opening and dusting: - It is the process of opens up the clumps of fibers into individual staples and at the same time delivers a uniform quantity of opened stock to the scouring train. This facilitates the proper penetration of the scouring liquor into the wool fibre, rendering the scouring more uniform and throughout. It also reduces cost by saving on soap alkali scouring liquor.
- 24. 5. Scouring: -It is washing the wool in warm water and in detergent solutions for the removal of impurities in raw wool. 6. Burr picking and carbonizing: - Wool contains a large or small amount of burr. • If the burrs are not removed they cause considerable difficulty in the manufacturing process and may damage card, clothing and combs. • The chemical removal of burr is known as carbonization. immersing the wool in a solution of sulfuric acid (H2SO4) that remove the vegetable matter present in the wool.
- 25. • 7. Oiling:- The wool is lubricated with oil emulsion to minimize the breakage of fibre during carding, reduce the fly waste and static electricity in carding and increase cohesion of the fibres in loose silver, thus facilitating drafting and spinning. Mostly non-ionic mineral emulsified oils are used in the strength of 3-5 per cent of wool weight. • In India mahua oil (for carpet industry) emulsified with crude soap is extensively used.
- 26. 8. Carding andspinning: Carding is done to further open the wool, straighten the individual fibre and remove natural impurities and delivering it in a convenient form for spinning. Three type of carding. a. Woolen carding b. Worsted carding c. Weaving 9. Dyeing and finishing:- It forms the final process in the preparation of wool ready to market.
- 27. Scouring • Scouring isthe process of removal of impurities in raw wool. It is accomplished by aqueous scouring (detergent method) process or by solvent degreasing (ether or benzene) method. • Scouring is accomplished in a series of vats or bowls (3-6) through which the wools propelled by mechanical rakes with intervening squeezers. • The squeezed stock is dried through specially constructed dryers.
- 28. Vegetable matter content Hand picking: Vegetable matter is separated by hand, is the most accurate but is also the most time consuming. Because its slowness the method is not suitable for large scale testing. Carbonizing : Chemical removal of burr is known as carbonization. It is done by using acids such as sulphuric or hydrochloric acid and or by salts such as aluminum chloride which produces acid when heated. Comparison: Scoured sample is immersed in a liquid of the same refractive index as wool (1.555). A suitable liquid is made from a mixture monochloronaphthalene and a petroleum distillate. The sample is illuminated from below by a special apparatus called Transparizer and various kinds of vegetable matter become apparent. Caustic soda: most rapid and most commonly used method for vegetable matter content determination, in which the wool is dissolved in boiling NaOH. This method requires the use of correction factors, since the boiling caustic soda dissolves a variable quantity of lignin and other components in the vegetable matter.