Also known as flaxseed oil, linseed oil is golden yellow, amber, or brown drying oil with a peculiar odor and bland taste. Iodine value 177, saponification value 189-195, acid number(max.) 4 (ASTMD 234-48), polymerizes on exposure to air. Soluble in ether, chloroform, carbon disulfide, and turpentine; slightly soluble in alcohol, spontaneous heating. Combustible. Chief constituents are glycerides of linolenic, oleic, linoleic, and saturated fatty acids. The drying property is due to the linoleic and linolenic groups. Derivation is from seeds of the flax plant Linum usitatissimum by expression or solvent extraction. Various refining and bleaching methods are used. The grades of linseed oil are raw; boiled, double-boiled, blown, varnish makers' and refilled.
Linseed oil is currently one of the highest known vegetable oils with the highest content of essential fatty acids (omega-3 and omega-6 fatty acids). Used in paints, varnishes, oilcloth, putty, printing inks, core oils, linings, and packings, alkyd resins, soap, and pharmaceuticals.