Rosin
Rosin is mainly extracted from the secretions of pine trees, which is a kind of natural resin which is extremely rich in nature and is also a renewable resource. The composition of rosin varies slightly with the origin of raw materials and processing methods, mainly composed of a mixture of resin acid and a small amount of neutral substances, of which resin acid is the main component, accounting for more than 90% of its total. Resinous acid is the general name of a class of isomers with the molecular formula C19H29COOH, which can be divided into conjugated double-bonded (abietic acid) resinous acid, non-conjugated double-bonded (imaric acid) resinous acid, dehydrogenated (dehydrogenated) and hydrogenated resinous acid. Rosin has many excellent properties due to its structural characteristics, such as anti-corrosion, moisture-proof, insulation, bonding, emulsification, etc., so it is widely used in materials, chemistry, chemical industry, electronics industry, medicine and pesticides. Rosin according to different raw material sources, can be divided into: (1) fat rosin. It is obtained from the processing of rosin collected from pine standing trees (see rosin processing). (2) Wood rosin. Extracted from akiko (resin-rich wood). (3) Rosin float. Wood pulp oil from sulphate pulping of conifers is obtained by fractionation. Since the 1980s, the annual production of rosin in the world has hovered around 1.1 million tons, of which the fat rosin accounts for 60-65%, the wood rosin accounts for 12-15%, and the floating rosin accounts for 23-27%. Rosin production countries are China, the United States, the Soviet Union, Portugal, Mexico, India, Sweden, Spain, Finland, Poland, Greece, the Federal Republic of Germany, France and other about 30 countries. China is rich in fat rosin, the annual output of rosin in the early 1980s reached 400,000 tons, becoming the world's largest production of fat rosin, the largest export country, wood rosin and oil rosin also have a certain development. The United States mainly produces floating rosin, followed by wood rosin, and little fat rosin. The Soviet Union mainly produces fat rosin, followed by wood rosin, and oil rosin is still scarce. |