Fiber Science

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Fiber Science

• Animal Fibers Lesson 2

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I. Wool production

• A. Wool has likely been used longer than any
  other fiber by humans to make clothing
• B. Early humans may have started using sheep
  skins for clothing
• 1. Soon discovered that the wool fibers could
  be twisted into thread
• 2. Realized animals did not have to be killed
  to harvest fibers and the animal continued to
  grow wool fiber
• 3. May even have started a selective breeding
  program to develop sheep with finer wool

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C. Wool is highly desired for fabric 1. Durable
2. Warm in the winter 3. Can be worn in the
summer because it absorbs moisture 4. Lends
itself to a variety of uses a. Fine
garments b. Durable garments c. Tapestriesd.
d. Blankets e. Rugs
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D. Wool animals 1. Sheep 2. Angora
goats 3. Alpacas 4. LLamas E. Wool
characteristics 1. Wool is made of type of
protein called keratin (also found in horns,
hooves, fingernails, and skins) 2. On animals,
wool has both primary follicles that produce
coarser, outer hair (designed to keep water away
from body) and finer, inner hairs that provide
insulation
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• 3. Wool grows by adding cells to the hair
  structure
• a. Cells overlap and resemble scales
• b. Scales help fibers mat and hold together
  (i.e. felt, yarn)
• 4. Wool has a wavy appearance crimp the more
  crimp, the more desirable the wool

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• 5. The skin secretes a grease-like substance from
  the skin that helps keep the wool soft, pliant,
  and able to shed water (live animal substance
  yolk processed substance lanolin)

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F. Wool processing

• 1. Wool is shorn from the sheep
• 2. Shorn wool is bundled together not cleaned
  and called grease wool
• 3. Process of cleaning (removing the yolk/foreign
  material) is called scouring

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• 4. Wool is graded (assigned a quality rating)
• 5. Wool is blended with other wool fibers to
  create a particular type of wool fabric
• 6. After blending, the fibers are untangled
  (called carding)
• 7. Carded fibers are spun and twisted together to
  form thread/yarn to be woven into cloth

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II. Silk production

• A. Silk probably originated in Ancient China
  around 2600 BC
• B. Hundreds of years later, silk was produced and
  marketed in many parts of Asia

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• C. Characteristics of silk
• 1. Silk is the strongest of all natural fibers
  and tends to hold its shape well
• 2. Silk fibers are very fine (.00059 to .00118
  inch in diameter), and very long
• (Length of fiber contributes to its strength)
• 3. Silk is very receptive to dyeing and shows
  colors well
• 4. Silk cloth is comfortable and absorbs
  moisture better than any of the other natural
  fibers

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D. Sericulture

• 1. Sericulture culture of the silk worm
• 2. Out of over 30,000 species of spiders and
  113,000 species of insects that make silk
  (insect order Lepidoptera) most silk is
  produced by the moth Bombyx mori.
• 3. Thailand, China, and Japan are leading
  countries in sericulture

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4. Silk-making process

• a. An adult female moth lays around 700 eggs
  (no larger than a pinhead) on specially prepared
  paper
• b. When the eggs begin to hatch, they are laid
  on bamboo frames covered with mulberry
  leaves
• c. Tiny larva hatch and feed on the leaves
• i. May devour 30,000 times their weight at
  hatching
• ii. May increase their hatch weight up to
  10,000 times

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• d. The larva grow for a period of about 35 days
• i. Larva shed their skins four times
• ii. Larva grow to a length of about 3 inches and
  ½ inch diameter

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• e. After the growth period, the larva attaches
  itself to a straw structure placed on the pad,
  and begins to spin a cocoon
• i. Silk material for the cocoon is secreted
  from two glands inside the larvas mouth
• ii. Silk is forced out of the mouth through two
  openings called spinnerets
• iii. The cocoon is completed in 2-3 days and
  may contain as much as a mile of silk filament

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• f. As the larva begins to go through
  metamorphosis, it is killed with heat and the
  silk collected some larva are allowed to
  continue living, grow into adults and are used
  for breeding/laying eggs
• g. Collection of silk filaments
• i. Each cocoon usually produces about 100 yards
  of combined filaments
• ii. Silk taken from the cocoon is called raw
  silk