| 摘要 |
PURPOSE: A manufacturing method of polyurethane is provided to provide polyurethane with excellent fatigue resistance and improved storage stability and mechanical properties. CONSTITUTION: A manufacturing method of polyurethane comprises: a step of obtaining two or more prepolymers by reacting two or more NCO group-containing diisocyanate having different reactivity with polyol with a molar ratio of 3-6:1 in a respective separate polymerization bath to obtain two or more prepolymers; a step of mixing the two or more prepolymers in one polymerization bath and adding one equivalent or more of polyol, a chain extender, an antifoaming agent and foaming agent based on separated NCO group of in the prepolymer. Diisocyanate with slow reactivity is dipenyl methane-4,4-diisocyanate and the other diisocyanate with quick reactivity is naphthalene-1,5-diisocyante. |
