koviöljyt

Koviöljyt, also known as hardening oils or drying oils, are a category of natural oils that undergo a chemical process called polymerization or oxidation when exposed to air, causing them to solidify or harden into a durable film. This transformation is distinct from non-drying oils, which remain liquid indefinitely. The key characteristic of koviöljyt is their ability to cure and form a protective surface.

The primary components responsible for this hardening property are unsaturated fatty acids, particularly those containing multiple double bonds within their molecular structure. Linoleic acid and linolenic acid are common examples found in koviöljyt. When oxygen from the air comes into contact with these unsaturated fatty acids, a complex series of reactions occurs, leading to the cross-linking of molecules and the formation of a solid, resinous layer.

Common examples of koviöljyt include linseed oil, tung oil, and soybean oil. These oils have been traditionally used in various applications, most notably in wood finishing, paints, varnishes, and inks. Their ability to penetrate wood and form a hard, protective surface makes them ideal for enhancing durability and providing a natural aesthetic. In paints and varnishes, they act as binders, holding pigments together and forming a flexible yet tough coating. The drying time can vary depending on the specific oil, environmental conditions, and whether any driers have been added to accelerate the process.