Explanation

natural resin mainly comes from amorphous hemimorph or solid organic matter of plant exudates. When heated, it becomes soft and can melt. It tends to flow under stress and is generally insoluble in water, but can be soluble in alcohols, ethers, ketones, and other organic solvents. According to the basic components of resin, they can be divided into three categories: ① pure resin, that is, resin like substances composed of terpenoids and crude essential oils. Such as rosin, etc. ② The gum containing resin or gum resin is composed of polysaccharides? It is soluble in water or swelling with water, but insoluble in alcohol and organic solvents. Such as frankincense. ③ Oily resin or gum refers to resin that contains more essential oil and can be dissolved in oil. According to the formation history of resin, it can be divided into fossil resin, semi fossil resin and fresh resin, the latter being the most important source of natural resin. natural resin is mainly used as coatings (see natural resin coatings), and can also be used as raw material for paper making, insulation materials, adhesive, medicines, spices, and decorative arts (such as amber); Another example is Canada glue (fir glue), whose refractive index is similar to that of ordinary glass, so it can be used as a transparent adhesive for optical devices such as microscopes.

Classification