Patent ID: 8178644
Filing Date: 2012-05-15
Classification: C08G

Abstract:
1. A clear polyurethane comprising the reaction product of: a) a prepolymer made by reacting a stoichiometric excess of an aliphatic polyisocyanate with a primary amine-terminated polyether with an amine functionality of about 2 and an average amino equivalent weight of 1000 to 1250, and in which the free —NCO content of the resulting prepolymer is about 18% to 23% by weight; wherein the prepolymer is formed in a reaction that is essentially free of a polyether other than the primary amine-terminated polyether and b) (i) a polyol having an average nominal hydroxyl functionality greater than or equal to 2 and is selected from the group consisting of (a) a polyester polyol triol, (b) a polyether glycol, and (c) a polyester polyol diol, and (ii) a curing agent that has isocyanate reactive groups, a functionality of 2 to 3 and a molecular weight of <400 selected from the group consisting of (a) dianhydrohexitol; (b) aromatic diamines; (c) cyclohexanedimethanols; and (d) aromatic ring containing diols.