The microstructures were examined by SEM, FT-IR spectra, tensible properties mole % of [NCO/OH], and particle size analyzer. Growing concerns in the environment-friendly industries have led to the development of solvent-free formulations that can be cured. We had synthesized the polyurethane resin having the ability to protect stainless steel against corrosion. Compared with general packing materials and coatings, this resin is highly stronger in intensity and longer durability. Polyurethane resins were composed of polyols, IPDI, silicone surfactant, catalyst and crosslink agent. Moreover, thermal fillers such as $Al_2O_3$, fume silica and $ZrO_2$ not only accelerated the curing rate but also improved the physical property as thermal barriers. The rigid segments of polyurethane in mechanical properties were due to crosslink agent and the increase of [NCO/OH]. In conclusion, the polyurethane microstructure with crosslink agent can be good material for themoset coating of metal substrates such as stainless steel.