The polymerization process produces different types of polyurethane with the properties of the material.

Monomers such as toluene diisocyanate, two benzene and other commonly used methane diisocyanate. Polyol divided into 3: simple Polyols (ethylene glycol, glycerol, etc.); hydroxyl terminated polyester oligomer containing, used for the preparation of polyester type polyurethane; containing hydroxyl terminated polyether oligomer, used for the preparation of polyether type polyurethane. Polymerization methods vary with the properties of materials. Synthetic elastomer first of preparation of low molecular weight diols, again with excess aromatic isocyanate reaction, generate isocyanate terminated pre polymer, again with Ding diol chain extender, thermal plastic elastomer; if the use of aromatic diamine chain extension and further crosslinking, casting elastomer. The pre polymer is expanded by hydrazine or two amine amine, and the elastic fiber is obtained, and the excess of the isocyanate is mixed with the catalyst and the foaming agent, and the hard foamed plastics can be directly obtained. If the monomer, polyether, water, catalyst and other mixed, one step reaction can be a soft foam. The monomer and the polyol can be reacted in the solution, and the coating can be obtained, and the adhesive is mixed and reacted with the use of the isocyanate monomer and the low molecular weight polyester or polyether.