WHAT ARE RESINS?
Resins are typically viscous substances that convert into rigid polymers through a curing process. They are naturally occurring but are now often made synthetically. Some of them have similar properties to natural plant resins, but many are very different.
Synthetic resins have several classes. Some are manufactured by the esterification of organic compounds. Some resins are more like thermosetting plastics in which the term “resin” is loosely applied to the reactant or product, or both. The term “resin” may be applied to one of two monomers in a copolymer, the other being called a “hardener.” For thermosetting plastics that only have one monomer, the sole monomer compound is called the “resin.” For example, liquid methyl methacrylate is generally called the “resin” or “casting resin” when it’s in a liquid or viscous state before it polymerizes and “sets.” The subsequent polymethyl methacrylate is often renamed acrylic glass or just acrylic.
