Natural Animal FIber - Wool

Lecturer em Good Shepherd Finishing School, Ooty
4 de Jun de 2015

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Natural Animal FIber - Wool

  1. UNIT 5 WOOL
  2. WOOL Prepared by – Biniya Arakkal Textile Science Faculty Institute of Design & Technology Surat
  3. About - Wool  Wool is natural animal fiber obtained from sheep.  It is composed of protein substance – Keratin.  Wool composed carbon, hydrogen, nitrogen & sulfur  It has crimps & curls thus gives a spongy feel as well as insulation for the wearer.  Color of fiber ranges from white to brown.  Removing wool from sheep is known as shearing.  After shearing, the wool is graded & scoured in alkaline solution.
  4. Wool
  5. Sheared Wool Scouring in Alkaline Solution
  6. Woolen & Worsted
  7. Wool  Next process is done depending upon woolen fabric or worsted products are to be made.  Wool is having low strength  Its water repellant and the water droplets can be brushed off easily from surface, it absorbs about 20% of water without feeling damp.  The fabrics of wool are intended for winter purpose because of its good insulating property.
  8. Characteristic of Wool The characteristic of protein fiber - wool  They are composed of amino acids.  They have excellent absorbency.  Moisture regain is high.  They tend to be warmer than others as they are bad conductors of heat.  Only natural fiber which has low tenacity or strength.  They have poor resistance to alkalis but good resistance to acids.  They have good elasticity and resiliency.
  9. Classification by Fleece 1. Lamb’s Wool – The fleece obtained by shearing the lamb is six to eight months old for the first time is known as lamb’s wool (First Clip). It has natural tapered end that gives it a softer feel. 2. Hogget Wool – This is the one obtained from the sheep about 12 to 14 months old that have not been previously shorn. The fiber is fine, soft, resilient and mature and has tapered ends. 3. Wether Wool – It is the one obtained from the sheep older than 14 months. The shearing is not done for the first time and in fact these fleeces are obtained after first shearing. 4. Pulled Wool – It is taken from animals originally slaughtered for meat. The wool is pulled from the pelt of the sheep using various chemicals. It produce low-grade cloth.
  10. Classification by Fleece 5. Dead Wool – This is wool obtained from the sheep that have died of age or accidentally killed. Dead wool fiber is decidedly inferior in grade. 6. Cotty Wool – This type of wool is obtained from the sheep that are exposed to severe weather. The cotty wool is of a poor grade and is hard and brittle. 7. Tag Locks – The torn, ragged, or discolored parts of a fleece are known as tag locks. These are usually sold separately as an inferior of wool. Cotty WoolTag Locks
  11. Manufacturing process of Wool Scouring Carding Spinning Woolen Yarns Drawing Roving Spinning Sorting & Grading Drying Oiling Ginning & Combing Worsted Yarns Preparation of the Fibers
  12. Process Preparation of Fiber  Fleece vary from 3 to 8 Kg in weight. The best quality wool is obtained from the sides and shoulders and is treated as one fleece.  The raw wool or newly sheared fleece is called grease wool as it contains natural oil.  The wool obtained should be carefully sorted into different grades. Sorting and Grading  Wool is sorted into sections of different quality fibers, from different parts of the body.  The best quality of wool is used for clothing; the lesser quality or second quality is used to make rugs.
  13. Process Scouring is the first step in conversion of greasy wool into a textile product. It is the process of washing wool in hot water and detergent. Machine contains warm water, soap and mild solution of soda ash or other alkali. If the raw wool is not sufficiently clear of vegetable substance after scouring, it is put through the carbonizing bath of dilute sulfuric acid or hydrochloric acid to burn out the foreign matter.
  14. Process Drying Wool after scouring should not be allowed to become absolutely dry. About 12 to 16% of moisture is left in the wool which would enable handling of the fibers in further processing.
  15. Process Oiling Wool is unmanageable after scouring and hence the fiber requires to be treated with various oils to keep it from becoming brittle. It also helps to lubricate for spinning operation.
  16. Process Carding is the process which depends up on whether woolen yarn or worsted yarns are to be produced. Manufacturing Woolen Yarn, the fiber passes through two stages  Carding  Spinning Carding:- Objective of carding is to disentangle the fiber  The wool fiber is passed between rollers covered with thousands of fine wire teeth.  Fibers are disentangled by the action of wires and are arranged parallel.  By using oscillating device, one thin film, or sliver of wool is placed diagonally and overlapping another sliver to give a fuzzy surface. Spinning:- This stage is similar to that of worsted production process.
  17. Process Manufacturing Worsted Yarns has involved different steps.  Carding  Gilling and Combing  Drawing  Roving  Spinning Carding:- This process is carried out in same way as carding process for woolen yarn. Gilling and Combing:- Gilling is carried out before (Preparative gilling) and after (Finisher gilling) combing.  Preparative gilling is mainly to align the fibers in parallel direction, blend the wool through doubling and to add moisture & lubricants.  Finisher gilling is mainly aimed to remove the mild entanglement introduced to the combed sliver.  Gilling process removes the shorter staple and straightens the longer fibers.  Combing removes shorter fibers 1 to 4” length (Comb noils), places longer fibers(tops) parallel.
  18. Principle system of spinning There are two principle system of spinning worsted yarn, they are; English System:- In English system(Bradford), the fiber is oiled before combing and a tight twist is inserted. This produce smoother and finer yarns. French System:- In this system, no oil is used. Yarn is given no twist, it is fuzzier therefore it is soft worsted yarn.
  19. Principle System Of Spinning Worsted yarn Fabric Woolen yarn Fabric
  20. Woolens Worsteds Processing – spun from wool fibers of oLength – spun from short fibers of 1-3” oDiameter- medium or coarse The fibers are washed, scoured & carded. Processing – spun from wool fibers of oLength – longer than 3” oDiameter- fine diameter. Fibers are washed, scoured, carded, combed and drawn. Yarn Bulky Uneven Low to medium slack twist Tensile strength lower than worsted Yarn Fine Smooth Even Tighter twist Higher tensile strength Fabric appearance oSoft oFuzzy oHeavier weight Fabric appearance oCrisp oSmooth oLighter weight Characteristics Insulator due to trapped air Doesnot hold a crease well Less durable than worsted Characteristics Less insulator Holds creases and shape More durable than woolens. Uses oSweater oCarpets oTweeds Uses oSuits oDresses oGabardines
  21. Gabardines
  22. Crepes
  23. Characteristics of Wool Fabric 1. Composition: The chief constituent is protein substance called Keratin. Chemically it contains carbon, hydrogen, oxygen, nitrogen and sulfur. 2. Strength: Wool is the weakest fiber. Fabric is strengthened by the use of ply yarns. It loses about 25% strength when wet 3. Elasticity: Each wool fiber is a molecular coil-spring making the fiber remarkably elastic. It can be stretched 25 to 30% of natural length and stretch up to 50% when wet. 4. Resilience: Wool is the most resilient fiber because it has a natural crimp that keeps its shape. 5. Drapability: Wool’s excellent draping quality is aided by its pliability, elasticity and resiliency. 6. Heat Conductivity: Wool fibers are non-conductor of heat, they permit the body to retain its normal temperature. It is natural insulator and keeps body warm in winter.
  24. Characteristics of Wool Fabric 7. Absorbency: Wool fiber is original wicking fiber. Wool can be easily absorb up to 30% of its weight in moisture without feeling damp. 8. Cleanliness and Washability: The wool adheres dirt and requires thoroughly cleaned. Care should be taken while laundering as the fiber is softened by moisture and heat which results in shrinking. 9. Reaction to Bleaches: Chlorine bleaches like sodium hypochlorite are harmful for wool. They can be bleach by hydrogen peroxide or sodium per borate. 10.Shrinkage: Wool shrink when washed. 11. Effect of Heat: Wool becomes harsh at 100C and begins to decompose at slightly higher temperature. It does not burn freely when touched by flame. 12.Effect of Light: Wool is weakened by prolonged exposure to sunlight.
  25. Characteristics of Wool Fabric 13.Resistance to Mildew: Moisture is the main factor for the development of mildew on a fabric. When fabric is left damp condition, mildew develops. 14.Resistance to Insects: Wool are especially vulnerable to the larvae of moths and such other insects as carpet beetles. 15.Reaction to Alkalis: Wool is quickly damaged by strong alkalis, which make it essential to use mild soap or detergent. 16.Reaction to Acids: Although wool is damaged by hot sulfuric acid, it is not affected by other acids. 17.Affinity for Dyes: The dye reaches the core of the fiber and bonds permanently. It absorbs many different dyes deeply, uniformly and directly without use of combining chemicals. 18.Resistance to Perspiration: Wool is weakened by alkali perspiration. Perspiration generally will cause discoloration
  26. Laundry  Wool laundered using mild detergent or shampoo as alkaline solution is harmful  Do not wring them for removing water, but can be rolled between the towel or absorbent pad.  Can be placed flat on paper to retain its original position .
  27. Storage  Wool should be stored in clean and dry vaccum bags with naphthalene balls to avoid the damage by moths, mildew and insects attack.
  28. Woolen fabrics
  29. Worsted fabric
  30. Summary  Wool fibers are animal fibers, which are obtained from sheep.  Wool, after shearing, it is graded and then scoured with alkaline solution. Then it is subjected to next process depending upon whether it is meant for worsted purpose or woolen products.  These are the only natural fibers, which have considerable low strength.  The color of fiber ranges from white to brown depending upon the nature of sheep from which it is sheared.  It is water repellent and the water droplets can be brushed off easily from the surface, it can also absorb about 20% of its water without feeling damp.  These fabrics are best intended for winter purpose.