Resin is a natural or synthetic compound that is very viscous and hardens under certain conditions. It is usually soluble in alcohol but insoluble in water. This compound is classified in different ways depending on its chemical composition and use. It also has many uses in art, polymer production, etc. Natural resin is obtained from plants. The best example is pine tree sap, which has a pungent smell. As you know, this material is very sticky, but it hardens over time. A number of other plants also produce resin, and these substances have been used by humans for thousands of years. Some plants exude a similar substance called gum, which does not react with water and is softer and more flexible. The color of plant resin varies from transparent to dark brown, and its degree of hardness and turbidity is different. Some of them are highly volatile because they contain unstable compounds. Misidentification of resinous trees can also sometimes cause accidents, because some of them contain heptane, which is a flammable and explosive hydrocarbon. The famous and ornamental substance amber is also obtained by the hardening of plant resin and is often found in dark golden color, which is the conventional color of plant resins. Amber is also seen in other rare colors such as blue. Humans have been using natural resins for thousands of years. Pine resin has been used for sealing boats, embalming corpses, food containers and other uses. It is also used in making varnish, polish, ink, perfume, jewelry and many other things. With the advancement of technology, mankind realized that this material can be turned into a polymer, and soon after that synthetic resins were discovered. In most cases, polymers are made with synthetic resins, which are cheaper and easier to purify. All types of synthetic resins are more stable, predictable and uniform than natural resins because they are made under controlled conditions and there is no possibility of gross products in it. They are made by combining chemicals in the laboratory and the result of the reaction is the formation of sticky compounds. This material can be used in the production of plastic, paint and many similar materials instead of natural resin. The types of resin are: • Polyester resin • Epoxy resin • Vinyl ester resin • Phenolic resin • Polyurethane resins • Other resins