Wool can be grouped into 3 big categories:
Sheep are typically shorn once a year and in some places twice. In the traditional way, still used in many countries, the woolen fleece of a sheep is cut off with blade shears or with machine shears (known as hand-pieces). In Australia, big sheep farms can reach 10.00 head of cattle. Big flocks of sheep are shorn by machine shearing operating a power-driven toothed blade quickly and efficiently for a maximum shearing of the animal. Once the fleece has been removed from the sheep, the fleece is collected and brought to another area for the selection. The first process is the skirting: the removal of pieces which are placed in separate containers. Then the fleece is folded, rolled with its best part above and it is examined for its quality in a process known as wool classing considering fine crimp, length, colour and general conditions.
Shear fleece is split up into:
Famous Lambswool is wool shorn from young sheep at around the age of eight months that have been shorn for the first time. It is a very good wool (19.5 micron), and a registered trademark (LAMBSWOOL) patented in 1984 by I.W.S (International Wool Secretariat) matched to the Woolmark brand to ensure the preservation of the extra-fine lamb's one.
Raw fleece, called greasy wool, is made of fibres agglutinated by grease and sweat residue as well as dirt, straw and other fibres. The semi-grease wool, free from impurities, is made of long fibres from 4/6 to 40 cm. It is a poor heat conductor, therefore it is very much appreciated for making warm fabrics. Wool is actually very nonconducting and protecting because of its structure that allows to keep air in the tangle of its elementary fibres.
Wool fiber has the highest degree of moisture absorption, but in the meantime it is highly water-repellent. If a drop of water falls on a wool fabric, once it has been removed, it does not leave any damp. Wool can absorb moisture almost up to the 33per cent of its own weight without giving the feeling of dampness. The reason is a chemical reaction: the fiber gives off heat while its molecules absorb moist – therefore the human body is best protected against any sudden jumps in temperature. Wool fiber is the less inflammable fiber overall, it has low heat of combustion, when it burns it forms a swollen and spongy char which is insulating and self-extinguishing.
Under the microscope, three basic layers are shown:
It is made of keratin, a protein rich in sulfur, an essential constituent of nails, hair and horns and by fats that – once purified – are known as lanolin. The quality and use of wool is determined by its fiber diameter, length crimp, elasticity, tensile strength and colour. Fiber diameter is the single most important wool characteristic determining its spinnable grade, that is the length of a spun yarn obtainable with a certain weight of wool.
Therefore, the finer the wool, the richer it is. The finest wool are also shorter and more crimp, such as Merino wool. Short fibres are typically 6-7 cm in length, while long fibres are superior (English long-wools can reach up to 40 cm!). Crimp gives wool softness, smoothness, elasticity, adhesion in spinning. The finer the wool, the more frequent and regular is its crimp. The most common colour is ivory white, but there are also gray, dark, black and reddish sheep.
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