Gum rosin is an organic compound of monoterpene, turpentine and resin acid. Also known as colophony or rosin, it is a solid form of pine oleoresin from pine trees (mostly conifers). It is produced by heating fresh liquid resin in order to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from pale yellow to amber. Rosin is brittle at room temperature, but melts at higher temperatures. It is insoluble in water and soluble in organic solvents. Gum Rosin also has a faint piny odour. It consists mostly of different resin acids, especially abietic acid.
Gum Rosin can be found in Indonesia where it is derived from the distillation of Oleo Pine Resin. Different grades of gum rosin like WW, WG and X grade are available. Gum Rosin is also found in China where they are also produced from Oleo Pine Resin. The species of pine tree include P.massoniana, P.yunnanenisis and P.elliottii. These pine trees are located in the forested areas on provinces of Yuanan, Guangzhou, Fujian, Jiangxi and Sichuan and southern of China.
Gum Rosin is produced from the crude pine resin collected from pine trees. The resin is subjected to distillation and the distillation process is carried out in large copper stills. The volatile liquid terpene components would separate from the mixture as it vaporizes at a temperature between 100 to 160⁰C, leaving behind fluid rosin as the distillate. This fluid rosin is collected and purified by passing it through straining wadding. The condensate left behind is called turpentine oil.
Adhesives & Sealants Industry
Rosin was widely used as an ingredient of some kind of adhesive, especially in heat melt adhesive, pressure sensitive adhesive and rubber adhesive. Rosin mainly is used to enhance the strength, plasticity and viscosity of adhesive.
Electrical Equipment Industry
Rosin is used as an insulation material in electric equipment industry. In China, there is a long history of applying rosin as an insulation material in cable industry. Rosin can also be mixed with bakelite and other artificial resin to soak and besmear electric loop.
Metal Processing Industry
Rosin is used as a soldering aid and metal polishing agent. Since it has a weak acidity, it is able to remove the oxidation film from metal surface which slightly erodes the surface of metal.
Paints & Coating Industry
Rosin is a basic material for paint industry because it dissolves easily in alcohol, gasoline, turpentine and other organic solvents. Rosin is converted to resinate, refined with drying oil (e.g. tung oil) and then mixed with volatility solvent to produce various lacquers. Rosin also takes an important role in producing road coating. It is first converted to rosin malefic ester, polymerized rosin or disproportionated rosin polyols ester, which are then used to make thermoplastic coating for road sign injunction.
Most rosin are applied to the paper industry as a sizing agent. Rosin paper sizing agent can prevent printing oil soaking and dispersing from paper, which improves the strength and smoothness of paper and also enhances the anti-abrasion of paper. However, crystal rosin is unfit as a paper sizing agent due to its difficulty of saponification which would subsequently spot the paper or even jam the pipe in paper sizing agent production.
Rosin can replace a part of grease to produce soap because it has a similar character with fatty acid and is cheaper than fatty acid.
Synthetic Rubber Industry
Rosin is used as a softener, dispersant and emulsification in synthetic rubber industry. It enhances the plasticity, tear strength, heat resistance, flexibility and anti-abrasion of synthetic rubber.
In the bactericide industry, rosin can be converted into abietylamine acetate for killing algae, bacteria, mildew, mollusk and others pest. In the construction materials industry, rosin is mainly used as concrete frothing agent and floor tiling adhesive. In the food industry, rosin can be converted into hydrogenated rosin which is then used to produce chewing gum. In the printing ink industry, rosin can act as a color carrier and enhance color adhesive ability in printing ink. Polymerized rosin can also be used to producing various special printing ink.