Polyurethanes based on polyester polyols, in general, exhibit higher tensile and tear properties, abrasion resistance, thermal stability, chemical resistance and weathering performance compared to polyether-based polyurethanes. They are preferred in the most demanding environments and applications. However, there is one weak point of polyester based polyurethanes. They are much more susceptible to hydrolysis compare with polyethers in polyurethanes. A part made of polyester based polyurethanes can gradually lose properties in a humid environment or water emersion.
2-Methyl-1,3-propanediol (MPO) based polyester polyols largely overcomes this deficiency due to the steric shielding of the ester linkage by the pendant methyl group on MPO, and greater hydrophobicity. MPOis an ideal diol intermediate for polyester polyols used in polyurethane elastomers (PURs). This is because MPOs unique structure enhances hydrolytic stability, affords liquid polyester polyols that are easier to handle, and demonstrates excellent compatibility in formulations.