Attività

One type of network-forming thermoset, polyurethane, is molded into parts such as automobile bumpers and inside panels through a process known as reaction PEEK Injection Molding, or RIM. The two liquid precursors of polyurethane are a multifunctional isocyanate and a prepolymer, a low-molecular-weight polyether or polyester bearing a multiplicity of reactive end-groups such as hydroxyl, amine, or amide. In the presence of a catalyst such as a tin soap, the two reactants rapidly form a network joined mainly by urethane groups. The reaction takes place so rapidly that the two precursors have to be combined in a special mixing head and immediately introduced into the mold.