Functional polyurea microcapsules were prepared by the conventional interfacial addition polymerization utilizaing 2,4-toluenediisocyanate dimer. The inner-blockedisocyanate(isocyanate dimer) can be used to prepare microcapsules having latent functionality that can be cleaved at high temperature to generate isocyanate functional groups. The particle size of the microcapsules obtained was a function of the agitation speed and the concentration of surfactants. Average particle diameters were in the range of 10 to 30 ${mu}{ extrm}{m}$. The oil-containing polyurea microcapsules of which average particle size of 10${mu}{ extrm}{m}$ were obtained at 4000 rpm and 3% surfactant concentration. Both the DSC thermogram and FTIR spectroscopic data showed that the uretdione ring was opened and then blocked isocyanates were reactivated at an elevated temperature of 25$0^{circ}C$.