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Wool grease is a sticky fat with a disagreeable odour, extracted from the soapy water in which the wool has been scoured or cloth fulled. It may also be extracted from greasy wool by means of volatile solvents (carbon disulphide, etc.). Wool grease does not consist of glycerol esters and, therefore, chemically it should be regarded as a wax rather than a fat. It is employed in the preparation of lubricants and for other industrial purposes, but it is mostly used as lanolin (its refined product) or for the extraction of wool grease olein or wool grease stearin.
Lanolin, obtained by purifying wool grease, has the consistency of an ointment; it ranges in colour from yellowish‑white to brown according to the degree of refining, deteriorates only very slightly in the air and has a faint, characteristic odour. Lanolin is very soluble in boiling spirit but insoluble in water, although it can absorb a large quantity of water, turning into an unctuous emulsion known as hydrated lanolin.
Anhydrous lanolin is used for the preparation of lubricants, emulsifiable oils or dressings. Hydrated or emulsified lanolin is mainly used for the preparation of ointments or cosmetics.
Slightly modified lanolin, which retains the essential character of lanolin, and wool alcohols (also known as lanolin alcohols ‑ mixtures of cholesterol, isocholesterol and other higher alcohols) are also covered by this heading.
The heading excludes chemically defined alcohols (generally Chapter 29) and preparations based on lanolin, for example lanolin to which medicated or perfumed substances have been added (heading 30.03 or 30.04, or Chapter 33). Also excluded are lanolins so extensively modified chemically that they have lost the essential character of lanolin, for example lanolin ethoxylated to such an extent as to be water soluble (usually heading 34.02).
When wool‑grease is steam‑distilled and pressed, it separates into a liquid, a solid and a residue.
The liquid, known as wool grease olein is cloudy, reddish‑brown and with a faint odour of wool grease. It is soluble in alcohol, diethyl ether, motor spirit, etc. It is used as a textile greasing agent in spinning mills.
The solid part (wool grease stearin) is a waxy substance, yellow‑brown in colour and smelling strongly of wool grease, soluble in boiling spirit and other organic solvents. It is used in the leather industry, for the preparation of lubricants or adhesive greases, and in the manufacture of candles or soap.
The heading excludes wool grease residues (heading 15.22).
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