Rosin

Rosin refers to a solid form of resin that is obtained from pines and some other plants, mostly conifers, which is produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black. At room temperature, rosin is brittle, but it melts at stove-top temperatures. It chiefly consists of different resin acids, especially abietic acid. Rosin is used for its chemical properties in a variety of industrial applications, including as a flux in soldering, in the making of varnishes and adhesives, and for treating the bows of stringed instruments to provide friction with the strings. In pharmaceuticals, rosin forms an ingredient in several plasters and ointments. Throughout its various applications, the properties of rosin can be modified by chemical transformation through the process of saponification, esterification, or hydrogenation, leading to the production of rosin esters, which are used in a broader range of manufacturing processes, including printing inks, paper sizing, soaps, and sealants.