The self-emulsified aqueous-based polyurethane (PU) consists of carboxyl group, which is an ionic center not only stabilizing the aqueous polymer dispersion but also serving as the curing site toward aziridinyl curing agent. Two new aziridinyl curing agents, HDI-AZ and ADA-AZ, are prepared from an addition reaction of aziridine to hexamethylene diisocyanate (HDI) and adipic acyl chloride (ADA), respectively. These curing agents are added separately into NCO-terminated PU prepolymer before or after the water dispersion process. The resulting PU dispersion becomes a single component self-curable aqueous-based PU system. The cured PU is obtained from this single component PU dispersion on drying at ambient temperature. The improved PU properties demonstrate the feasibility of this convenient single component self-curable aqueous-based PU system. (C) 2003 Wiley Periodicals, Inc.