Abstract: A continuous process for the preparation of a thermoplastic polyurethane elastomer is disclosed. The process is carried out at 130 to 250° C. and comprises reacting at least one polyether diol with at least one organic diisocyanate and 1,4-di-(2,2′-hydroxyethyl)-hydroquinone, in the presence of tin dioctoate as a catalyst. The resulting thermoplastic polyurethane has a glass transition temperature (Tg) below 50° C. The inventive thermoplastic polyurethane is suitable for making injection molded or extruded articles.

Abstract: A method for making a bloom-free thermoplastic polyurethane is disclosed. The method entails blending a chain terminator such as monofunctional alkylene alcohol having at least 14 carbon atoms, mono-isocyanate and mono-amine, in a thermoplastic polyurethane that would, but for the blending of the chain terminator of the invention, feature a blooming defect. The polyurethane suitable for the use in the inventive process is the product of a reaction wherein reactants comprise (i) at least one hydroxy functional polyol such as polyester polyol, polyether polyol and polycarbonate polyol, having a number average molecular weight of 500 to 5000 and a hydroxyl functionality of at least 2, (ii) a chain extending compound, and (iii) an organic diisocyanate. The ratio NCO/H characterizing the relative amounts of named reactants is 0.95 to 1.05. The addition of the chain terminator renders the product bloom-free.