Wool

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Wool
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The Wool Fiber

• Growth
• A. Wool fibers grow from follicles in the skin.
• B. Growth and elongation occurs at the base of
  the fiber and not at the tip.
• C. The processes of growth are continuous.
• D. Shearing apparently does not particularly
  stimulate growth of wool fibers.

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The Wool Fiber

• 2. Feature of Wool Fiber
• A. Diameter may vary from .0003 to .002 inch.
• B. Number of fibers per square inch may vary
  form 5000 to 50,000.
• C. Length may vary form 1 to 20 inches.
• D. Practically all wool has crimp. Crimp is the
  natural indentation of waviness in the fibers.
  The number of crimp per inch of fiber ranges
  form 10-36. Crimp affects the length of wool
  may increase length by 30. In general, the
  more crimp per inch, the finer the fiber.
• E. Wool has a high tensile strength, 17 tons per
  square inch of fiber.
• F. Elasticity due primarily to the cystine
  content of the fiber partly to the crimp.

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The Wool Fiber

• 3. Chemical CompositionConsiderable variation.
• A. Pure wool is composed mainly of Keratin, an
  insoluble protein, which is the chief
  constituent of hair, feathers, horns, and
  hooves.
• B. Cystine is the main constituent of Keratin
  (about 13). It is in the cystine that sulfur is
  present in the wool. (sulfur content of clean
  wool is about 3.4).

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The Fleece or Grease Wool

• Variation of wool fibers on the body.
• A. The finest and dense wool fibers are found on
  the shoulders about midway between the top of the
  shoulder and the floor of the chest.
• B. The shortest wool is on the belly.

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2. General characteristics of wool.

• A. Wool is not quickly inflammable, but it will
  burn and give off a very disagreeable odor.
• B. Electricity and heat transfer through wool
  slow.
• C. Softness of the wool is the opposite to
  harshness it wiry sometimes dues to lack of
  yolk.
• D. Purity- purity is related to the kind and
  color of the fiber of which the fleece is
  composed. Kemp is the most important of the
  purity defects. Black fibers may also be called
  an impurity.
• E. Color- color is partly tint ,luster or
  brightness. White is preferred.
• F. Uniformity- Fibers of uniform grade over the
  badly. Sought but never completely achieved.

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3. Adhering material in raw wool.

• Some of these are not necessarily disadvantages
  as they may be essential to the proper
  preservation of the fiber while it is being
  developed to a length suitable for use.
• A. Yolk- Primarily cholesterol and is secreted
  for the preservation of the fiber. More yolk is
  secreted by fine, dense fleeced sheep.
• B. Suint-(pronounced swint) A potassium salt
  produced by the sweat gland. It is usually
  mixed with yolk. It may be the source of odor
  associated with sheep.
• C. vegetable Matter - such burns, chaff, seed,
  etc.
• D. Dirt- varies from one part of the country to
  the other.
• E. Moisture-gives a certain character to wool
  which makes it easier to work. I some cases
  these materials make up a greater percentage of
  the entire weight than does the wool fiber.

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4. Shrinkage

• The percentage loss in weight of grease wool due
  to scouring. Shrinkage varies widely in different
  fleeces from 20-80.
• A. Estimated shrinkage according to grade
• low Medium High
• Fine Wool 60 61-67 68
• Half-blood 56 57-64 65
• Three-eights blood 52 53-59 60
• Quarter Blood 45 46-54 55
• Low quarter 40 41-49
  50

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Shrinkage Con.

• B. Range wool shrinks more than farm wool
  generally because farm wools are coarser.
• C. Yield 100 minus shrinkage (in ) yield
• D. Grease price clean wool price x yield
• E. Clean Price Grease price x 100
• Yield
• F. Most shrinkage is estimated
• G. Shrinkage is influenced primarily by dirt and
  yolk.

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5. Classes of wool

• Two general classes of apparel wool are combing
  and clothing wool. This classification is based
  on length of fiber. Sometimes an intermediate
  class is used which is called French combing.
• Combing wooltops worst cloth
• Clothing wool noils
• As wool increases in coarseness it must also
  increase in length to be combed.
• Grade Length of necessary for combing
• Fine 2 ¾
• Half blood 3
• Three-eights blood 3 ¼
• Quarter blood 3 ½
• Low quarter blood 4
• Clothing wool, 1 ½ shorter French combing in
  between

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6. Grades of Wool

• Grades of wool are based primarily on fineness
  (diameter of fiber) and variation in fiber
  diameter. Fine wool makes finer fabrics than
  coarse wool and usually sell for a higher price
  per pound, however in the grease, fine wool may
  sell for less per pound, due to shrinkage.
• Grades of wool may be given in either the
  American or Bradford (English) system. These
  systems have different terminology, but are based
  on the relative fineness of fiber.

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Grades of Wool Con.

• Wool Class American Bradford Breed
• Fine Fine 80-70-64 Merino,
  Ranbouillet, Debouillet
• Half-blood 62-60
  Targhee,Southdown
• Three-eights blood
  58-56 Corriedale, Columbia,
  Hampshire
• Medium Quarter
  Blood 54-50
  Shropshire, Dorset,
  Cheviot
• Low quarter blood
  48-46 Romney and coarse
  crossbreds
• Common
  44-40 Lincoln, Cotswold,
• Leicester
• Long
  Braid 36

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7. Factors affecting the value of wool

• Clean Wool Grease Wool
• Grade A. Grade
• Length B. Length
• Strength, purity, etc. C. Shrinkage

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8. Manufactures of wool

1. Sorting separating various parts of the fleece
   according to fineness.
2. Scouring- a cleaning process- warm water and
   dilute alkali- which removes dirt, grease, and
   some vegetable matter.
3. Carding- clean wool is passed through a machine,
   which tends to straighten out the fibers. This
   yarn is usually used for woolen cloth.
4. Combing- a machine process which draws the fiber
   out in a parallel direction. Wool must be certain
   length to comb.

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Biological Development of the Wool Fiber

• Structure of the skin
• A. wool fibers are outgrowths of the skin
• B. skin consists of an outer layer, the
  epidermis and a much thicker layer, the dermis
  or corium
• C. the loose layer of connective tissue beneath
  the skin is know as the tela subcutanea
• D. underlying this layer is the panniculus
  adiposous or subcutaneous fatty tissue

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2. General Development of the Individual Skin
Follicles

• Two types of follicles
• 1. primary- usually the largest and arranged in
  rows in the skin in groups of three
• 2. Secondary-are the most numerous and lie to
  one side of the primaries
• B. The primary trio with its associate secondary
  follicles constitute the follicle group and is
  known as the basic unit of wool production.

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3. Structure of the Fiber

• Epicuticle- a thin outer membrane covering the
  cuticle
• Cuticle- makes up a protective layer of
  overlapping, flattened cells, called scales.
• Cortex- the major component of the wool fiber and
  imparts many special properties including
  elasticity, resiliency, and durability.
• Orthocortex- referred to a soft and has a higher
  affinity for dyes and is found at the outside of
  the curve of the fiber.
• Paracortex-found on the inside of the curve of
  the fiber and is referred to a the hard and
  maintains less affinity for dyes.
• Medulla- central core-is found primarily in the
  medium and coarse wools. Medulation is considered
  to be caused form incomplete keratinization.
  Basically, the fiber is wider than the follicles
  ability to produce kertain and hollow or spongy
  core results.

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4. Three types of fibers produces by sheep

1. Wool fibers-true fibers and referred to as crimp
   or waviness found on the fiber
2. Med- hair or heterotype- medullated and tend to
   be finer than kemp fibers as well as true fibers
   , yet generally lack crimp.
3. Kemp-coarsest fibers grown by sheep and are shed
   seasonally. Tend s top be short, chalky white,
   brittle, and do not appear to accept dyes well.
   They are harsh handling, yet important in the
   manufacturing of weeds.