reçine

Reçine, or resin, is a viscous organic substance produced by many plants, notably conifers, as a defense mechanism and to seal wounds. It is secreted by specialized ducts and may harden on exposure to air. When resin contains significant volatile oils it is called an oleoresin; the volatile fraction can be removed by distillation to yield a solid residue known as rosin, while the volatile component is often recovered as turpentine. In Turkish, reçine is the word for resin, borrowed from French résine.

Natural resins differ from fossil resins; amber is fossilized resin. Resins are distinct from gums, which are typically more water-soluble. Resins may be purified and modified for industrial uses, including varnishes, paints, adhesives, and inks.

Chemical composition is dominated by terpenoids and related compounds. Common constituents include monoterpenes and diterpenes such as alpha-pinene and abietic acids, along with various resin acids, waxes, and sometimes essential oils. Over time resins can polymerize, becoming hard and brittle, which affects their physical properties and applications.

Sources and processing involve tapping living trees such as pines and firs to collect exudates. The collected material can be heated to drive off volatiles, yielding turpentine (solvent) and rosin (solid residue). Rosin and purified resins are used in varnishes, lacquers, adhesives, and as additives in printing inks and other products.

Applications span traditional uses like incense and medicinal preparations to modern roles in coatings, optical resins, and as soldering flux or violin bow rosin. Safety considerations include flammability and potential allergic reactions; rosin dust can pose occupational hazards in some settings.