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compounds that have molecular weights below 350, based on the weight of the reaction mixture. 

4. The polyurethane polymer of any preceding claim, which contains no more than 20 ppm of metals and in addition contains no more than 0.05 weight percent of amine group-containing compounds that have molecular weights of below 350 except for the alkoxylated Mannich base. 

6. The polyurethane polymer of any preceding claim wherein polyol b-1) has a hydroxyl equivalent weight of at least 400. 

6. A process for making a polyurethane polymer comprising reacting, in one or more steps that include a final curing step in which the isocyanate index is 90 to 150, reactants comprising 

a) at least one organic polyisocyanate; and 

b) polyols comprising b-1) at least one polyol having a hydroxyl equivalent weight of greater than 250 g/mol, and b-2) one or more polyols having a hydroxyl equivalent weight of up to 250, wherein at least 50% by weight of b-2) is at least one alkoxylated Mannich base having an average hydroxyl functionality of 3 to 7; 

wherein the hard segment content of the polyurethane polymer is 20 to 80% by weight of the polyurethane polymer and the density of the polyurethane polymer is at least 760 kg/m$^{3}$. 

7. The process of claim 6 wherein the alkoxylated Mannich base is represented by the structure: 

<img src='content_image/955119.jpg'>

wherein each R is independently hydrogen, linear or branched alkyl having 1 to 18 carbon atoms or linear or branched alkenyl having 1 to 18 carbon atoms, m is a number from 0 to 2, each R 1 is independently hydrogen or linear or branched 

