| abstract |
A thermoset polyurethane composition having excellent impact and optical properties is prepared from a formulation comprising at least a prepolymer and a chain extender. The prepolymer includes an isocyanate component, containing 1,3-bis(isocyanatomethyl)cyclohexane and at least (20) percent by weight of 1,4-bis(isocyanatomethyl)cyclohexane, and an isocyanate-reactive component, containing hydroxyl, amine or thiol functionality. The isocyanate-reactive component includes from (70) to (95) percent by weight of a compound having a molecular weight from 150 to less than 950 Daltons, and from (5) to (30) percent by weight of a compound having a molecular weight from 2,000 to 4,500 Daltons. The chain extender is an aromatic, aliphatic, or cycloaliphatic polyamine compound containing at least one hydroxyl and/or thiol group. Articles that may be prepared include ophthalmic lenses, vehicle glazings, aircraft canopies, and the like. |