Wool fibre
Wool production and use dates back approximately 10,000 years in Asia Minor. People living in the Mesopotamian Plain at that time used sheep for three basic human needs: food, clothing and shelter. As spinning and weaving skills developed woollens became a greater part of people's lives. The warmth of wool clothing and the mobility of sheep allowed people to spread civilisation beyond the warm climate of the Mesopotamia. Between 3000-1000 BC the Persians, Greeks and Romans distributed sheep and wool throughout Europe. The Romans took sheep everywhere they built their Empire including the British Isles. From here the British took sheep to all their colonies.
Fibre Structure
Wool is different to other fibres because of its chemical structure. This chemical structure influences its texture, elasticity, staple and crimp formation. Wool is a protein fibre, composed of more than 20 amino acids. These amino acids form protein polymers. Wool also contains small amounts of fat, calcium and sodium.
Types of Wool Yarn
There are two types of wool yarn – woollens and worsteds.
Woolens: Woolens is a general term describing various fabrics woven from woollen yarn that is spun from the shorter wool fibres. These shorter fibres are not combed to lie flat as in the worsted yarn. This results in soft surface textures and finishes and the weave of individual yarns does not show as clearly as in worsted fabrics.
Worsteds: Worsted is a general term for fabrics woven from worsted yarns that contain longer fibres spun from combed wool. Worsted wool refers to tightly woven, smooth, clear finished goods in a variety of twill and other stronger weaves.
Worsteds undergo several processes:
- Scouring – Washed to remove dust, suint (sweat) and wool wax.
- Carding – Rolled with a roller that is covered with teeth tease apart the staples of wool, laying the fibres nearly parallel to form a soft rope called a 'sliver'.
- Combing – Combed to separate short from long fibres, ensuring that the long fibres are laid parallel to produce a combed sliver called a 'top'.
- Drawing – Drawing out of tops into the thickness of one, to thoroughly blend the wool and ensure evenness or regularity of the resulting 'roving'.
- Finisher drawing – Drawing to reduce the roving thickness to suit the spinning operation and further improve evenness.
- Spinning – Inserting twist into the yarn to give strength to the finished yarn.
Worsted vs woollen fabrics
- Worsted fabrics are often more expensive than wool spun products due to the longer raw material to resultant yarn processing route used.
- Worsted fabric is stronger and wears better than a woollen spun fabric of equivalent weave construction and fabric weight.
- Worsted fabrics are preferred for trousers, suitings, other garments and upholstery fabrics where a smooth finish is required.
- Woollen spun fabrics are used for jackets, coats, skirts, upholstery fabrics, rugs and blankets where bulk and textured finishes are desirable.
Wool has many beneficial properties which have led to its long history of use.
- Insulation. Wool insulates against heat and cold. It is comfortable in both hot and cold weather because it absorbs moisture vapour. The crimp in the wool fibres makes them stand apart from each other trapping insulating air between the fibres. Still air is one of the best insulators found in nature. In hot weather the absorption/evaporation process works to help keep the body cooler.
- Fire resistant. Wool does not have to be specially treated to become non-flammable. A fabric made entirely of wool is difficult to ignite, burns slowly, and has limited ability to sustain a flame. Wool does not melt when burned and so cannot stick to the skin and cause serious burns.
- Water repellent. Although wool can absorb moisture, it repels liquids. It is naturally hydrophobic. The scales on the outside of the fibre cause liquid to roll off the surface of the fabric. Even if wool does eventually get wet it generates heat and keeps the body warm, not cold and clammy.
- Elastic. Wool has greater elasticity than any other plant or animal fibre. Wool can be twisted, turned and stretched and will still return to its natural shape.
- Durable. The interlocking protein molecules in the fibres of wool have the power to elongate, stretch and recover, creating an extremely robust fabric that will last. Each wool fibre is made up of millions of 'coiled springs' that stretch and give rather than break.
- Static resistant. Wool has very little tendency to collect static electricity because wool naturally absorbs moisture from the air. Wool garments are much less likely to 'spark' or cling to the body.
- Noise insulation. Wool absorbs noise and reduces noise levels.
- Dirt resistant. Wool's ability to absorb moisture and therefore its low build-up of static electricity means that wool does not attract lint and dust from the air. The crimp in the fibre and the scales on the outside of the fibre deep dirt from penetrating the fabric.
- Versatile. Different sheep breeds with their own unique fibre characteristics provide different wools for a wide range of products.
- Dye-ability. Wool is easy to dye. The scales on the surface of the wool fibre diffuse light giving less reflection and a softer colour. The proteins in the core of the fibre absorb and combine with a wide variety of dyes and allows the wool to hold its colour.
- Comfort. Wool is comfortable to wear because of its elasticity, and moisture absorbing qualities.
- Fashionable. Wool drapes well, is alive, flexible and tailors easily, making it sought after by fashion designers.
Despite the elastic properties and its fire resistance, wool garments and products are often chemically treated as follows:
- Shrink proofing
- Fire proofing
- Moth proofing.
It is important to look at how the fibre was produced, as some animal treatments can leave chemical residue in the fibre. Post shearing treatments are also a cause for concern. Organically grown fibres can still be treated with toxic chemicals for the 'proofings' mentioned above, and these chemicals can cause health problems. Because of the scales on the wool fibres wool is often itchy and can cause an allergic reaction in some people.
Australia is the world's largest producer of wool.
Australian Wool Production
Did you know...
- In 2003/2004 there were 106 million sheep shorn in Australia producing 480 million kg of greasy wool.
- It is expected that the amount of wool produced in 2004/2005 will rise by 4% to 500 million kg of greasy wool from 112 million sheep shorn.
- The Australian flock was composed of 84.6% Merino, 11.3% crossbred, 4.1% other breeds at 30 June 2003.
- The wheat-sheep zone of Australia contains around 55% of the Australian sheep flock, the high rainfall zone contains around 33% and the pastoral zone contains around 12%.
- At 30 June 2003, 73% of the total wool produced in Australia is produced by less than 40% of wool producing farms.
Did you know...
- Australia is the world's largest producer of wool, producing over a quarter of the world's greasy wool in 2003/2004.
- While Australia produces more wool than any other country, China has the largest sheep population. Australia has the second largest sheep population.
- Australia exports wool to 50 countries. China is the biggest purchaser of Australian wool, with exports to China valued at $1.1 billion in 2003/2004.
- In 2003/2004, wool accounted for 2.5% of Australia's total exports, 3.4% of Australia's primary industry (agricultural/mining) exports, and 9.4% of Australia's agricultural exports, ranking third behind beef and wheat.
- Wool exports were valued at $2.8 billion in 2003/2004.
Did you know...
- Australian wool accounted for 48% of the total used in global wool apparel in 2003/2004.
- In 2003, wool accounted for 2.4% of total world fibre use and about 3.5% of world apparel fibre use (with Australian wool approximately 2.3% of world apparel fibre use).
- Casual leisurewear is the largest clothing sector accounting for 70% of the total apparel market.
- Young adults, who dominate global discretionary apparel expenditure, are influenced more by price and performance rather than the textile fibre used.
- Worsted fabrics are made with longer fibres that produce a surface that's smooth to touch. Woollens are made with shorter fibres that stand up from the surface and give the fabric a hairy touch.
- Wool insulates against heat and cold, is healthy, water repellent, fire resistant, naturally elastic, wears longer, is versatile, resists static, insulates against noise, resists dirt, is easy to sew, is comfortable and dyes beautifully.
Sources for 'Did you know' sections: The Woolmark Company, AWTA Ltd, Australian Wool Industries Secretariat, Australian Wool Production Forecasting Committee, ABARE.