Wool fiber – Basics, Characteristics, & Properties
Wool is possibly the oldest fiber known to humans. It was one of the first fibers to be spun into yarn and woven into the fabric.
Of the major apparel fibers, wool is the most reusable and recyclable fiber on the planet. The eco-credentials of wool are enhanced by its long service life and suitability to be recycled to new textiles for clothing, resilient upholstery or products that call on its natural resistance to fire and temperature extremes. Aside from premium next-to-skin apparel, wool can be used in industrial applications such as thermal and acoustic insulation or in pads to soak up oil spills.
At the disposal stage, natural fibers such as wool reduce the impact of the textile industry on pollution and landfill build-up. In warm, moist conditions such as in soil, wool biodegrades rapidly through the action of fungi and bacteria to essential elements (i.e. Nitrogen and Sulphur) for the growth of organisms as part of natural carbon and nutrient cycles.
Wool is possibly the oldest fiber known to humans. It was one of the first fibers to be spun into yarn and woven into a fabric. Wool mostly comes from sheep but also from alpacas, camels, and goats. Australia, Eastern Europe, New Zealand, and China are major wool producers. The American woolen industry began in the Massachusetts settlements in 1630, where each household was required by law to produce wool cloth.
How is wool made?
First, our sheep needs to grow it!
Then, they need a haircut. The process is called sheering. A sheering specialist can sheer 200 sheep in a day. A ewe, or female sheep, can produce up to 15 pounds of wool. A ram, or male sheep, can 20 pounds of wool. The sheared wool is called raw wool and since sheep don’t take showers, it must first be cleaned.
Next, the wool is carded – that means brushing the wool to straighten the fibers. Once done by hand, these days a carding machine passes the wool through a series of rollers covered with wire bristles. The carded fibers are gently scraped into strands called roving. The roving is spun into yarn that is then woven into cloth. In the past, the task of spinning usually was the job of unmarried females – they became spinsters.
A fleece is a wool taken from a single animal in a shearing. But not all wool is equal – even when it comes from the same animal. The highest quality wool comes from the sides, shoulders, and back. The lowest quality comes from the lower legs.
Wool is graded for fineness and length. The length varies from place to place on the animal, but it mostly varies amongst sheep breeds. Australian Merino wool is 3-5 inches long. Breeds found in Texas and California produce fibers 2.5 inches long. Wool from other breeds and other animals may be as long as 15 inches.
Properties & Uses
This microscopic view shows us why wool is special. The surface is a series of overlapping scales of protein, pointing toward the tip. On the animal, this enables the foreign matter to work its way out of the fleece. In a strand of yarn, it enables the fibers to lock with one another. This is the key to wool’s strength.
Wool’s surface repels water. Since moisture does not remain on the surface, woolen fabrics tend to feel dry and comfortable even in damp weather. The inner core does absorb moisture – so much so that wool can absorb almost double its own weight in water and still feel reasonably dry. This absorbency also gives wool its natural resistance to wrinkles. The absorbed moisture also holds down static electricity. And because of the inner moisture, wool is naturally flame resistant.
Wool today is prized for its beauty and durability. It is still the prime choice for high-quality business suits, warm sweaters, and premium carpets.
Characteristics of Wool Fibers and Products
- A protein fiber
- Flame resistant (wool usually extinguishes itself when the source of flame is removed)
- Weaker than cotton or linen, especially when wet
- Fibers range from one to fourteen inches long
- Most valued for its textured appearance and warmth
- Must be washed gently or dry cleaned
- Can be damaged by chlorine bleach
- Moths and carpet beetles eat wool
- Springs back into shape after being crushed
- An excellent insulator as woolens (80% air)
- Absorbs moisture which is held inside the fiber (the wool will still feel dry even on a humid day)
- Accepts dyes easily (“dyed in the wool”)
- Quality of wool varies with the breed of sheep
- Does not attract dirt or static electricity
- Wool products labeling Act permits the word “wool” to be used for fibers from sheep, Angora or Cashmere goats, camel, alpaca, llama, and vicuna.
- Wool is a protein fiber that comes from a variety of animals.
- Sheering is done by hand, but the manufacturing of wool fabric is done by machine.
- Wool is ideal for cool weather garments such as sweaters.