Resin refers to a class of polymer compounds foundational to modern manufacturing. It is produced by chemically polymerizing and processing raw materials derived from petroleum, natural gas, and other sources to replicate the properties of natural resins. 

Resins are broadly classified into two types.

Thermoplastic resins: These melt when heated and harden when cooled, making them recyclable and well-suited for mass production. 

Thermosetting resins: Once cured, these do not remelt even when heated and will char or decompose instead; they offer excellent heat resistance, chemical resistance, and mechanical strength.