Linseed oil – it's processed vegetable oils. They are used to produce coatings on their own or mixed with color pigments and resins. For linseed oil also include solutions of alkyd resins and some other organic compounds. Natural drying oils are made from recycled vegetable oils and substances that speed up their drying – driers. The composition of semi-subsistence and artificial drying oils include, in addition, organic solvents, which regulate the viscosity of the varnish. The solvents used primarily petrol-solvent, turpentine. Processing of vegetable oils in the varnish is in their cooking, and the introduction of driers.
Vegetable oils are not suitable for cooking oil paints and varnishes. Drying them on too long, and produced films have insufficient water resistance and lower mechanical properties. When heated vegetable oils (with desiccant) is in the process of polymerization of the molecules of oil, formed high molecular weight compounds, which provide an oil film, high moisture resistance and improved mechanical properties. Semi-subsistence varnishes are made from vegetable oils, which are natural plant oils subjected to even more dramatic chemical changes as a result of the strong heat treatment or adding chemicals that cause transesterification of oil molecules. Artificial drying oils – is the third group of drying oils, which are derived from synthetic film-forming substances.
They are often called synthetic, which is not entirely true, since most of the raw materials for them to receive not through the synthesis of elements, and waste treatment chemical industry. Natural drying oils (flax and hemp). Contain no solvents. Their produce almost exclusively – from drying vegetable oils, mainly flax and hemp. Linseed varnish have a light yellow color and are suitable for making white and light colored oil paints. Color hemp drying oil is much darker.