Polyester, Polyether and Polycaprolactone are the three main chemical classes of TPU films.
Credit: Huntsman
Polycarbonate Diols (PCDs)
Another interesting class of polyols used for thermoplastic polyurethane production is Polycarbonate diols. Generally used to produce polyurethanes that incorporate the carbonate linkages for superior performance. Polycarbonate-polyurethanes can also be produced through the use of polycarbonate-based polyurethane prepolymers.
A polycarbonate-based polyurethane prepolymer is a derivative of the corresponding polycarbonate diol in which all the polyol hydroxyl (OH) end groups have been reacted with an isocyanate leaving isocyanate groups (NCO) at the termini instead of hydroxyls.
When compared to polycaprolactone and PTMEG-based polyurethanes, PU elastomers based on PC-PU prepolymers exhibit:
Extreme durability
Higher chemical resistance
Improved hydrolytic stability
Greater thermal resistance
Better abrasion resistance, and
Superior mechanical properties