Resins

Originally this was the name given to natural products commonly called fat (Yani) but now it has become widely used. There are two kinds of resin: natural resin and synthetic resin. Natural resin is a metabolic product of plants, (unlike shellac which is a secretion of insects). For example when scratching the bark of a pine tree, pine resin is secreted. This is not a polymeric compound but rather terpene is the main component. On the other hand, a synthetic resin is like the Japanese name for plastics, because phenolic resin exhibited properties that were like rosin, even though it is in fact totally different, and so the name was born. Although it is historical, it is still used as a resin, like alkyd resin, for example.