This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation, storage, etc. of polytetramethylene ether glycol-bis(para-aminobenzoate) (hereinafter referred to as P-250). This standard applies to compounds prepared by esterification of polytetramethylene ether glycol (PTMEG) with an average molecular weight of 250 and p-aminobenzoic acid or transesterification reaction with p-aminobenzoic acid ester compounds. The product is mainly used as a vulcanizing agent for polyurethane elastomers and can also be used to cure epoxy resins.