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Fiber Science . Animal Fibers Lesson 2. 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
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Fiber Science Animal Fibers Lesson 2
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
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
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
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
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)
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
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
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
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
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
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
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
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 larva’s 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
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