This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation, storage, etc. of 1,3-propanediol-bis(4-aminobenzoate) ester (hereinafter referred to as 740M). This standard applies to 740M produced from 1,3-propanediol and benzocaine through transesterification reaction, recrystallization and other processes. The product is mainly used as a chain extender for polyurethane elastic materials and can also be used to cure epoxy resin.