Ethylenediamine and high carbon ethyleneamine in the ethylenamine series can produce polyamide resins with low relative molecular weight. Polyamide main fat with low relative molecular weight is the condensation polymerization of dimeric acid and diamine or ethylene polyamine. It is divided into two categories: reactive and non-reactive. The former is mainly used as a curing agent for surface coatings and adhesives, and is widely used in shipbuilding, automobiles, civil construction and other fields; the latter is mainly used as a hot melt adhesive and ink, plastic printing, electronic and electrical and textile printing and dyeing fields