Scientifically, an epoxy or polyepoxide coating is what is known as a “thermosetting copolymer.” It is a copolymer because it is formed from the combination of two different materials, namely an epoxide resin and a polyamine hardener. The hardener is effectively a catalyst that promotes polymerization. The polymerization process produces extensive cross-linking of the two materials contributing to the compound’s strength.
Epoxy coating is thermosetting because mixing the resin and hardener triggers polymerization, or curing, that generates heat. The polymerization process can be controlled by carefully varying the proportion of resin and hardener and the prevailing temperature. Some applications benefit from extended curing and high heat. The curing period can vary from minutes to hours or days.