Epoxy resins are a class of prepolymers and polymers containing more than one epoxide group. Through a chemical reaction called curing, epoxy resins are processed with other chemicals to produce epoxy plastics (more commonly known as epoxies). The vast majority of epoxy resins are industrially produced petroleum derivatives. Today, hundreds of resins are available, the most common produced with epichlorohydrin and Bisphenol A.