Synthetic resin is a kind of artificially synthesized high molecular weight polymer. It is a resin that has or exceeds the inherent characteristics of natural resins. ASTM D883-65T defines synthetic resins as solid, semi-solid, or pseudo (quasi) solid organic substances with an unrestricted molecular weight but often high molecular weight. They tend to flow when stressed, often have a softening or melting range and when broken Shell-shaped.
In practical applications, it is often used synonymously with polymers and even plastics, especially referring to the basic materials produced by the polymerization reaction of monomers without any additives or with only a small amount of additives. In addition, it is sometimes used to represent uncured flowable thermosetting polymer materials.