Abstract: The present invention teaches a new process to produce novel, hard, optically clear, impact-resistant polyurethane polymers that are characterized by excellent thermo mechanical properties and chemical resistance, and the polymers made as a result of such a process. The polyurethanes are made by reacting in a one step process 1) a stoichiometric excess of aliphatic polyisocyanate whereby the index is between 95 to 120; 2) a primary amine-terminated polyether with an amine functionality of about 2 and a molecular weight of greater than 400; 3) a polyol having an average hydroxyl functionality greater than or equal to 2 and an average hydroxyl equivalent weight of from about 300 to about 2,000, and 4) an aromatic diamine; wherein component 3 must less be present in a ratio of less than five to one stoichiometric equivalents relative to equivalents of component 2, and 5) optionally, a cross linking agent.

Abstract: The present invention teaches a new process to produce novel, hard, optically clear, impact-resistant polyurethane polymers that are characterized by excellent thermo mechanical properties and chemical resistance, and the polymers made as a result of such a process. The polyurethanes are made by reacting a) a prepolymer made by reacting a polyisocyanate with a primary amine-terminated polyether with an amine functionality of about 2 and a molecular weight of >1000, and in which the free —NCO content of the resulting prepolymer is >18% by weight; with b) (i) a polyol having an average hydroxyl functionality greater than or equal to 2 and an average hydroxyl equivalent weight of from about 300 to about 1,000, and (ii) a curing agent that has isocyanate reactive groups, a functionality of 2 to 3 and a molecular weight of <400.